diff --git a/models/user/user.go b/models/user/user.go
index 8a39eca634..956e69edcf 100644
--- a/models/user/user.go
+++ b/models/user/user.go
@@ -1140,9 +1140,16 @@ func GetUsersBySource(ctx context.Context, s *auth.Source) ([]*User, error) {
 	return users, err
 }
 
+// CoAuthorUser represents a co-author parsed from a commit trailer, with optional Gitea user.
+type CoAuthorUser struct {
+	GiteaUser        *User
+	TrailerSignature *git.Signature
+}
+
 // UserCommit represents a commit with validation of user.
 type UserCommit struct { //revive:disable-line:exported
-	User *User
+	User      *User
+	CoAuthors []*CoAuthorUser
 	*git.Commit
 }
 
@@ -1158,6 +1165,27 @@ func ValidateCommitWithEmail(ctx context.Context, c *git.Commit) *User {
 	return u
 }
 
+// CoAuthorsFromCommit resolves co-author signatures from a commit into CoAuthorUser values.
+func CoAuthorsFromCommit(ctx context.Context, c *git.Commit) ([]*CoAuthorUser, error) {
+	sigs := c.CoAuthorSignatures()
+	if len(sigs) == 0 {
+		return nil, nil
+	}
+	emails := make([]string, len(sigs))
+	for i, sig := range sigs {
+		emails[i] = sig.Email
+	}
+	emailUserMap, err := GetUsersByEmails(ctx, emails)
+	if err != nil {
+		return nil, err
+	}
+	coAuthors := make([]*CoAuthorUser, len(sigs))
+	for i, sig := range sigs {
+		coAuthors[i] = &CoAuthorUser{GiteaUser: emailUserMap.GetByEmail(sig.Email), TrailerSignature: sig}
+	}
+	return coAuthors, nil
+}
+
 // ValidateCommitsWithEmails checks if authors' e-mails of commits are corresponding to users.
 func ValidateCommitsWithEmails(ctx context.Context, oldCommits []*git.Commit) ([]*UserCommit, error) {
 	var (
@@ -1168,6 +1196,9 @@ func ValidateCommitsWithEmails(ctx context.Context, oldCommits []*git.Commit) ([
 		if c.Author != nil {
 			emailSet.Add(c.Author.Email)
 		}
+		for _, sig := range c.CoAuthorSignatures() {
+			emailSet.Add(sig.Email)
+		}
 	}
 
 	emailUserMap, err := GetUsersByEmails(ctx, emailSet.Values())
@@ -1177,9 +1208,21 @@ func ValidateCommitsWithEmails(ctx context.Context, oldCommits []*git.Commit) ([
 
 	for _, c := range oldCommits {
 		user := emailUserMap.GetByEmail(c.Author.Email) // FIXME: why ValidateCommitsWithEmails uses "Author", but ParseCommitsWithSignature uses "Committer"?
+		coAuthorSigs := c.CoAuthorSignatures()
+		var coAuthors []*CoAuthorUser
+		if len(coAuthorSigs) > 0 {
+			coAuthors = make([]*CoAuthorUser, 0, len(coAuthorSigs))
+			for _, sig := range coAuthorSigs {
+				coAuthors = append(coAuthors, &CoAuthorUser{
+					GiteaUser:        emailUserMap.GetByEmail(sig.Email),
+					TrailerSignature: sig,
+				})
+			}
+		}
 		newCommits = append(newCommits, &UserCommit{
-			User:   user,
-			Commit: c,
+			User:      user,
+			CoAuthors: coAuthors,
+			Commit:    c,
 		})
 	}
 	return newCommits, nil
diff --git a/modules/git/commit.go b/modules/git/commit.go
index b576451db8..4a23533d2f 100644
--- a/modules/git/commit.go
+++ b/modules/git/commit.go
@@ -17,10 +17,11 @@ import (
 )
 
 type CommitMessage struct {
-	MessageRaw   string
-	messageUTF8  *string
-	messageTitle *string
-	messageBody  *string
+	MessageRaw       string
+	messageUTF8      *string
+	messageTitle     *string
+	messageBody      *string
+	messageCoAuthors *[]*Signature
 }
 
 // Commit represents a git commit.
@@ -68,6 +69,113 @@ func (c *CommitMessage) MessageBody() string {
 	return *c.messageBody
 }
 
+// cutTrailerPrefix matches "<token>:" case-insensitively at the start of line and
+// returns the trailing value plus whether a match was found. `git interpret-trailers`
+// matches trailer tokens case-insensitively, so e.g. "Co-Authored-By:" is valid.
+func cutTrailerPrefix(line, token string) (string, bool) {
+	if len(line) < len(token)+1 || line[len(token)] != ':' {
+		return "", false
+	}
+	if !strings.EqualFold(line[:len(token)], token) {
+		return "", false
+	}
+	return line[len(token)+1:], true
+}
+
+func isTrailerLine(line string) bool {
+	token, rest, ok := strings.Cut(line, ":")
+	if !ok || strings.TrimSpace(rest) == "" {
+		return false
+	}
+	for _, r := range token {
+		if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '-' {
+			continue
+		}
+		return false
+	}
+	return token != ""
+}
+
+// CoAuthorSignatures parses "Co-authored-by:" and "Co-committed-by:" trailers
+// from the trailing block of the commit message and returns deduplicated
+// Signature values. Only the last paragraph of the body is scanned so that
+// quoted or in-body occurrences (e.g. inside a revert/cherry-pick description)
+// are not misinterpreted as trailers. The trailing paragraph must contain only
+// trailer-shaped lines.
+// Token matching is case-insensitive to match git's behaviour.
+func (c *CommitMessage) CoAuthorSignatures() []*Signature {
+	if c.messageCoAuthors != nil {
+		return *c.messageCoAuthors
+	}
+	var sigs []*Signature
+	seen := make(map[string]struct{})
+	body := strings.TrimRight(c.MessageBody(), "\r\n")
+	if idx := strings.LastIndex(body, "\r\n\r\n"); idx >= 0 {
+		body = body[idx+4:]
+	} else if idx := strings.LastIndex(body, "\n\n"); idx >= 0 {
+		body = body[idx+2:]
+	}
+	lines := strings.Split(body, "\n")
+	for i, line := range lines {
+		lines[i] = strings.TrimRight(line, "\r")
+		if !isTrailerLine(lines[i]) {
+			c.messageCoAuthors = &sigs
+			return sigs
+		}
+	}
+	for _, line := range lines {
+		rest, ok := cutTrailerPrefix(line, "Co-authored-by")
+		if !ok {
+			rest, ok = cutTrailerPrefix(line, "Co-committed-by")
+			if !ok {
+				continue
+			}
+		}
+		rest = strings.TrimSpace(rest)
+		name, emailWithBracket, ok := strings.Cut(rest, " <")
+		if !ok {
+			continue
+		}
+		email, _, ok := strings.Cut(emailWithBracket, ">")
+		if !ok {
+			continue
+		}
+		email = strings.ToLower(strings.TrimSpace(email))
+		if _, exists := seen[email]; exists {
+			continue
+		}
+		seen[email] = struct{}{}
+		sigs = append(sigs, &Signature{Name: strings.TrimSpace(name), Email: email})
+	}
+	c.messageCoAuthors = &sigs
+	return sigs
+}
+
+// CoAuthorSignatures returns the commit's co-author trailers with the commit's
+// own author and committer emails filtered out, so a contributor who copies
+// themselves into a Co-authored-by line is not duplicated in the avatar stack.
+func (c *Commit) CoAuthorSignatures() []*Signature {
+	raw := c.CommitMessage.CoAuthorSignatures()
+	if len(raw) == 0 {
+		return raw
+	}
+	exclude := make(map[string]struct{}, 2)
+	if c.Author != nil {
+		exclude[strings.ToLower(strings.TrimSpace(c.Author.Email))] = struct{}{}
+	}
+	if c.Committer != nil {
+		exclude[strings.ToLower(strings.TrimSpace(c.Committer.Email))] = struct{}{}
+	}
+	out := make([]*Signature, 0, len(raw))
+	for _, sig := range raw {
+		if _, skip := exclude[sig.Email]; skip {
+			continue
+		}
+		out = append(out, sig)
+	}
+	return out
+}
+
 // ParentID returns oid of n-th parent (0-based index).
 // It returns nil if no such parent exists.
 func (c *Commit) ParentID(n int) (ObjectID, error) {
diff --git a/modules/git/commit_test.go b/modules/git/commit_test.go
index a7668e4deb..08116b0199 100644
--- a/modules/git/commit_test.go
+++ b/modules/git/commit_test.go
@@ -208,3 +208,92 @@ func Test_GetCommitBranchStart(t *testing.T) {
 	assert.NotEmpty(t, startCommitID)
 	assert.Equal(t, "95bb4d39648ee7e325106df01a621c530863a653", startCommitID)
 }
+
+func TestCoAuthorSignatures(t *testing.T) {
+	cases := []struct {
+		name string
+		body string
+		want []Signature
+	}{
+		{
+			name: "empty",
+			body: "title",
+			want: nil,
+		},
+		{
+			name: "single co-author",
+			body: "title\n\nbody text\n\nCo-authored-by: Jane <jane@example.com>",
+			want: []Signature{{Name: "Jane", Email: "jane@example.com"}},
+		},
+		{
+			name: "case insensitive token",
+			body: "title\n\nCo-Authored-By: Jane <Jane@Example.com>\nco-committed-by: Bob <bob@example.com>",
+			want: []Signature{
+				{Name: "Jane", Email: "jane@example.com"},
+				{Name: "Bob", Email: "bob@example.com"},
+			},
+		},
+		{
+			name: "dedup by lowercased email",
+			body: "title\n\nCo-authored-by: Jane <jane@example.com>\nCo-authored-by: Janey <JANE@example.com>",
+			want: []Signature{{Name: "Jane", Email: "jane@example.com"}},
+		},
+		{
+			name: "in-body trailer ignored, only last paragraph counts",
+			body: "title\n\nCo-authored-by: Mallory <mallory@example.com>\n\nactual body explaining revert\n\nCo-authored-by: Jane <jane@example.com>",
+			want: []Signature{{Name: "Jane", Email: "jane@example.com"}},
+		},
+		{
+			name: "body text in trailing paragraph rejects co-author line",
+			body: "title\n\nbody text\nCo-authored-by: Jane <jane@example.com>",
+			want: nil,
+		},
+		{
+			name: "missing brackets is ignored",
+			body: "title\n\nCo-authored-by: Jane jane@example.com",
+			want: nil,
+		},
+		{
+			name: "CRLF line endings",
+			body: "title\r\n\r\nCo-authored-by: Jane <jane@example.com>\r\nCo-committed-by: Bob <bob@example.com>",
+			want: []Signature{
+				{Name: "Jane", Email: "jane@example.com"},
+				{Name: "Bob", Email: "bob@example.com"},
+			},
+		},
+		{
+			name: "non-trailer line",
+			body: "title\n\nSigned-off-by: Jane <jane@example.com>",
+			want: nil,
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			cm := CommitMessage{MessageRaw: tc.body}
+			got := cm.CoAuthorSignatures()
+			assert.Len(t, got, len(tc.want))
+			for i, w := range tc.want {
+				if i >= len(got) {
+					break
+				}
+				assert.Equal(t, w.Name, got[i].Name, "name[%d]", i)
+				assert.Equal(t, w.Email, got[i].Email, "email[%d]", i)
+			}
+		})
+	}
+}
+
+func TestCommitCoAuthorSignaturesFiltersAuthorAndCommitter(t *testing.T) {
+	c := &Commit{
+		Author:    &Signature{Name: "Jane", Email: "jane@example.com"},
+		Committer: &Signature{Name: "Bob", Email: "bob@example.com"},
+		CommitMessage: CommitMessage{MessageRaw: "title\n\n" +
+			"Co-authored-by: Jane Self <jane@example.com>\n" +
+			"Co-authored-by: Bob Self <BOB@example.com>\n" +
+			"Co-authored-by: Carol <carol@example.com>"},
+	}
+	got := c.CoAuthorSignatures()
+	if assert.Len(t, got, 1) {
+		assert.Equal(t, "carol@example.com", got[0].Email)
+	}
+}
diff --git a/modules/repository/commits.go b/modules/repository/commits.go
index 32550a9f03..83ae10d8f5 100644
--- a/modules/repository/commits.go
+++ b/modules/repository/commits.go
@@ -29,9 +29,16 @@ type PushCommit struct {
 	AuthorName     string
 	CommitterEmail string
 	CommitterName  string
+	CoAuthors      []*PushCommitCoAuthor `json:",omitempty"`
 	Timestamp      time.Time
 }
 
+// PushCommitCoAuthor represents a co-author in a push commit payload.
+type PushCommitCoAuthor struct {
+	Name  string
+	Email string
+}
+
 // PushCommits represents list of commits in a push operation.
 type PushCommits struct {
 	Commits    []*PushCommit
@@ -148,6 +155,17 @@ func (pc *PushCommits) AvatarLink(ctx context.Context, email string) string {
 	return v
 }
 
+func pushCommitCoAuthorsFromSignatures(sigs []*git.Signature) []*PushCommitCoAuthor {
+	if len(sigs) == 0 {
+		return nil
+	}
+	coAuthors := make([]*PushCommitCoAuthor, len(sigs))
+	for i, sig := range sigs {
+		coAuthors[i] = &PushCommitCoAuthor{Name: sig.Name, Email: sig.Email}
+	}
+	return coAuthors
+}
+
 // CommitToPushCommit transforms a git.Commit to PushCommit type.
 func CommitToPushCommit(commit *git.Commit) *PushCommit {
 	return &PushCommit{
@@ -157,10 +175,34 @@ func CommitToPushCommit(commit *git.Commit) *PushCommit {
 		AuthorName:     commit.Author.Name,
 		CommitterEmail: commit.Committer.Email,
 		CommitterName:  commit.Committer.Name,
+		CoAuthors:      pushCommitCoAuthorsFromSignatures(commit.CoAuthorSignatures()),
 		Timestamp:      commit.Author.When,
 	}
 }
 
+// AuthorSignature returns the push commit author as a git signature.
+func (pc *PushCommit) AuthorSignature() *git.Signature {
+	return &git.Signature{
+		Email: pc.AuthorEmail,
+		Name:  pc.AuthorName,
+	}
+}
+
+// CoAuthorUsers returns co-authors in the template view shape.
+func (pc *PushCommit) CoAuthorUsers() []*user_model.CoAuthorUser {
+	if len(pc.CoAuthors) == 0 {
+		return nil
+	}
+	coAuthors := make([]*user_model.CoAuthorUser, len(pc.CoAuthors))
+	for i, coAuthor := range pc.CoAuthors {
+		coAuthors[i] = &user_model.CoAuthorUser{TrailerSignature: &git.Signature{
+			Name:  coAuthor.Name,
+			Email: coAuthor.Email,
+		}}
+	}
+	return coAuthors
+}
+
 // GitToPushCommits transforms a list of git.Commits to PushCommits type.
 func GitToPushCommits(gitCommits []*git.Commit) *PushCommits {
 	commits := make([]*PushCommit, 0, len(gitCommits))
diff --git a/modules/repository/commits_test.go b/modules/repository/commits_test.go
index 46db7b028b..6228ae61a7 100644
--- a/modules/repository/commits_test.go
+++ b/modules/repository/commits_test.go
@@ -145,14 +145,23 @@ func TestCommitToPushCommit(t *testing.T) {
 		ID:            sha1,
 		Author:        sig,
 		Committer:     sig,
-		CommitMessage: git.CommitMessage{MessageRaw: "Commit Message"},
+		CommitMessage: git.CommitMessage{MessageRaw: "Commit Message\n\nCo-authored-by: Jane Doe <jane@example.com>"},
 	})
 	assert.Equal(t, hexString, pushCommit.Sha1)
-	assert.Equal(t, "Commit Message", pushCommit.Message)
+	assert.Equal(t, "Commit Message\n\nCo-authored-by: Jane Doe <jane@example.com>", pushCommit.Message)
 	assert.Equal(t, "example@example.com", pushCommit.AuthorEmail)
 	assert.Equal(t, "John Doe", pushCommit.AuthorName)
 	assert.Equal(t, "example@example.com", pushCommit.CommitterEmail)
 	assert.Equal(t, "John Doe", pushCommit.CommitterName)
+	if assert.Len(t, pushCommit.CoAuthors, 1) {
+		assert.Equal(t, "jane@example.com", pushCommit.CoAuthors[0].Email)
+		assert.Equal(t, "Jane Doe", pushCommit.CoAuthors[0].Name)
+	}
+	assert.Equal(t, &git.Signature{Email: "example@example.com", Name: "John Doe"}, pushCommit.AuthorSignature())
+	if assert.Len(t, pushCommit.CoAuthorUsers(), 1) {
+		assert.Equal(t, &git.Signature{Email: "jane@example.com", Name: "Jane Doe"}, pushCommit.CoAuthorUsers()[0].TrailerSignature)
+		assert.Nil(t, pushCommit.CoAuthorUsers()[0].GiteaUser)
+	}
 	assert.Equal(t, now, pushCommit.Timestamp)
 }
 
diff --git a/options/locale/locale_en-US.json b/options/locale/locale_en-US.json
index c7ec133e57..b5ae421266 100644
--- a/options/locale/locale_en-US.json
+++ b/options/locale/locale_en-US.json
@@ -2589,6 +2589,11 @@
   "repo.diff.review.reject": "Request changes",
   "repo.diff.review.self_approve": "Pull request authors can't approve their own pull request",
   "repo.diff.committed_by": "committed by",
+  "repo.diff.coauthored_by": "co-authored by",
+  "repo.commits.coauthor_and": "and",
+  "repo.commits.coauthor_people": "%d people",
+  "repo.commits.coauthor_others_1": "%d other",
+  "repo.commits.coauthor_others_n": "%d others",
   "repo.diff.protected": "Protected",
   "repo.diff.image.side_by_side": "Side by Side",
   "repo.diff.image.swipe": "Swipe",
diff --git a/routers/web/repo/blame.go b/routers/web/repo/blame.go
index 803397f33f..62697d708c 100644
--- a/routers/web/repo/blame.go
+++ b/routers/web/repo/blame.go
@@ -29,12 +29,14 @@ import (
 type blameRow struct {
 	RowNumber int
 
-	Avatar         template.HTML
 	PreviousSha    string
 	PreviousShaURL string
 	CommitURL      string
 	CommitMessage  string
 	CommitSince    template.HTML
+	AuthorUser     *user_model.User
+	CoAuthors      []*user_model.CoAuthorUser
+	Author         *git.Signature
 
 	Code         template.HTML
 	EscapeStatus *charset.EscapeStatus
@@ -221,13 +223,10 @@ func processBlameParts(ctx *context.Context, blameParts []*gitrepo.BlamePart) ma
 	return commitNames
 }
 
-func renderBlameFillFirstBlameRow(repoLink string, avatarUtils *templates.AvatarUtils, part *gitrepo.BlamePart, commit *user_model.UserCommit, br *blameRow) {
-	if commit.User != nil {
-		br.Avatar = avatarUtils.Avatar(commit.User, 18)
-	} else {
-		br.Avatar = avatarUtils.AvatarByEmail(commit.Author.Email, commit.Author.Name, 18)
-	}
-
+func renderBlameFillFirstBlameRow(repoLink string, part *gitrepo.BlamePart, commit *user_model.UserCommit, br *blameRow) {
+	br.AuthorUser = commit.User
+	br.CoAuthors = commit.CoAuthors
+	br.Author = commit.Author
 	br.PreviousSha = part.PreviousSha
 	br.PreviousShaURL = fmt.Sprintf("%s/blame/commit/%s/%s", repoLink, url.PathEscape(part.PreviousSha), util.PathEscapeSegments(part.PreviousPath))
 	br.CommitURL = fmt.Sprintf("%s/commit/%s", repoLink, url.PathEscape(part.Sha))
@@ -243,7 +242,6 @@ func renderBlame(ctx *context.Context, blameParts []*gitrepo.BlamePart, commitNa
 
 	buf := &bytes.Buffer{}
 	rows := make([]*blameRow, 0)
-	avatarUtils := templates.NewAvatarUtils(ctx)
 	rowNumber := 0 // will be 1-based
 	for _, part := range blameParts {
 		for partLineIdx, line := range part.Lines {
@@ -258,7 +256,7 @@ func renderBlame(ctx *context.Context, blameParts []*gitrepo.BlamePart, commitNa
 			}
 
 			if partLineIdx == 0 {
-				renderBlameFillFirstBlameRow(ctx.Repo.RepoLink, avatarUtils, part, commitNames[part.Sha], br)
+				renderBlameFillFirstBlameRow(ctx.Repo.RepoLink, part, commitNames[part.Sha], br)
 			}
 		}
 	}
diff --git a/routers/web/repo/commit.go b/routers/web/repo/commit.go
index 6c973696ff..b54a1dbf9b 100644
--- a/routers/web/repo/commit.go
+++ b/routers/web/repo/commit.go
@@ -382,6 +382,11 @@ func Diff(ctx *context.Context) {
 	verification := asymkey_service.ParseCommitWithSignature(ctx, commit)
 	ctx.Data["Verification"] = verification
 	ctx.Data["Author"] = user_model.ValidateCommitWithEmail(ctx, commit)
+	if coAuthors, err := user_model.CoAuthorsFromCommit(ctx, commit); err != nil {
+		log.Error("CoAuthorsFromCommit: %v", err)
+	} else {
+		ctx.Data["CoAuthors"] = coAuthors
+	}
 	ctx.Data["Parents"] = parents
 	ctx.Data["DiffNotAvailable"] = diffShortStat.NumFiles == 0
 
diff --git a/routers/web/repo/view.go b/routers/web/repo/view.go
index 2d95d5233e..d0cf7d6f6f 100644
--- a/routers/web/repo/view.go
+++ b/routers/web/repo/view.go
@@ -135,6 +135,12 @@ func loadLatestCommitData(ctx *context.Context, latestCommit *git.Commit) bool {
 		ctx.Data["LatestCommitVerification"] = verification
 		ctx.Data["LatestCommitUser"] = user_model.ValidateCommitWithEmail(ctx, latestCommit)
 
+		if coAuthors, err := user_model.CoAuthorsFromCommit(ctx, latestCommit); err != nil {
+			log.Error("CoAuthorsFromCommit: %v", err)
+		} else {
+			ctx.Data["LatestCommitCoAuthors"] = coAuthors
+		}
+
 		statuses, err := git_model.GetLatestCommitStatus(ctx, ctx.Repo.Repository.ID, latestCommit.ID.String(), db.ListOptionsAll)
 		if err != nil {
 			log.Error("GetLatestCommitStatus: %v", err)
diff --git a/services/repository/gitgraph/graph_models.go b/services/repository/gitgraph/graph_models.go
index fc2eb85b87..fb33d3c0a0 100644
--- a/services/repository/gitgraph/graph_models.go
+++ b/services/repository/gitgraph/graph_models.go
@@ -93,9 +93,7 @@ func (graph *Graph) AddCommit(row, column int, flowID int64, data []byte) error
 // before finally retrieving the latest status
 func (graph *Graph) LoadAndProcessCommits(ctx context.Context, repository *repo_model.Repository, gitRepo *git.Repository) error {
 	var err error
-	var ok bool
-
-	emails := map[string]*user_model.User{}
+	emailSet := map[string]struct{}{}
 	keyMap := map[string]bool{}
 
 	for _, c := range graph.Commits {
@@ -106,12 +104,45 @@ func (graph *Graph) LoadAndProcessCommits(ctx context.Context, repository *repo_
 		if err != nil {
 			return fmt.Errorf("GetCommit: %s Error: %w", c.Rev, err)
 		}
-
 		if c.Commit.Author != nil {
-			email := c.Commit.Author.Email
-			if c.User, ok = emails[email]; !ok {
-				c.User, _ = user_model.GetUserByEmail(ctx, email)
-				emails[email] = c.User
+			emailSet[c.Commit.Author.Email] = struct{}{}
+		}
+		for _, sig := range c.Commit.CoAuthorSignatures() {
+			emailSet[sig.Email] = struct{}{}
+		}
+	}
+
+	allEmails := make([]string, 0, len(emailSet))
+	for email := range emailSet {
+		allEmails = append(allEmails, email)
+	}
+	var emailUserMap *user_model.EmailUserMap
+	if len(allEmails) > 0 {
+		emailUserMap, err = user_model.GetUsersByEmails(ctx, allEmails)
+		if err != nil {
+			log.Error("GetUsersByEmails: %v", err)
+		}
+	}
+
+	for _, c := range graph.Commits {
+		if c.Commit == nil {
+			continue
+		}
+		if c.Commit.Author != nil && emailUserMap != nil {
+			c.User = emailUserMap.GetByEmail(c.Commit.Author.Email)
+		}
+		coAuthorSigs := c.Commit.CoAuthorSignatures()
+		if len(coAuthorSigs) > 0 {
+			c.CoAuthors = make([]*user_model.CoAuthorUser, 0, len(coAuthorSigs))
+			for _, sig := range coAuthorSigs {
+				var giteaUser *user_model.User
+				if emailUserMap != nil {
+					giteaUser = emailUserMap.GetByEmail(sig.Email)
+				}
+				c.CoAuthors = append(c.CoAuthors, &user_model.CoAuthorUser{
+					GiteaUser:        giteaUser,
+					TrailerSignature: sig,
+				})
 			}
 		}
 
@@ -248,6 +279,7 @@ func newRefsFromRefNames(refNames []byte) []git.Reference {
 type Commit struct {
 	Commit       *git.Commit
 	User         *user_model.User
+	CoAuthors    []*user_model.CoAuthorUser
 	Verification *asymkey_model.CommitVerification
 	Status       *git_model.CommitStatus
 	Flow         int64
diff --git a/templates/repo/blame.tmpl b/templates/repo/blame.tmpl
index 8bdefa5d43..e6ae31891d 100644
--- a/templates/repo/blame.tmpl
+++ b/templates/repo/blame.tmpl
@@ -43,7 +43,7 @@
 								<div class="blame-info">
 									<div class="blame-data">
 										<div class="blame-avatar">
-											{{$row.Avatar}}
+											{{template "repo/commit_coauthor_avatar_stack" dict "AuthorUser" $row.AuthorUser "AuthorSignature" $row.Author "CoAuthors" $row.CoAuthors}}
 										</div>
 										<div class="blame-message muted-links" title="{{$row.CommitMessage}}">
 											{{ctx.RenderUtils.RenderCommitMessageLinkSubject $row.CommitMessage $row.CommitURL $.Repository}}
diff --git a/templates/repo/commit_coauthor_avatar_stack.tmpl b/templates/repo/commit_coauthor_avatar_stack.tmpl
new file mode 100644
index 0000000000..f9bd9e031c
--- /dev/null
+++ b/templates/repo/commit_coauthor_avatar_stack.tmpl
@@ -0,0 +1,35 @@
+{{if .CoAuthors}}
+	{{- $additionalClasses := .AdditionalClasses -}}
+	{{- $coCount := len .CoAuthors -}}
+	{{- $maxCo := 9 -}}
+	{{- $visibleCo := .CoAuthors -}}
+	{{- $overflow := 0 -}}
+	{{- if gt $coCount $maxCo -}}
+		{{- $visibleCo = slice .CoAuthors 0 $maxCo -}}
+		{{- $overflow = Eval $coCount "-" $maxCo -}}
+	{{- end -}}
+	<span class="coauthor-avatar-stack-wrapper {{$additionalClasses}}">
+		<span class="coauthor-avatar-stack">
+			{{- if .AuthorUser -}}
+				<a href="{{.AuthorUser.HomeLink}}" data-tooltip-content="{{.AuthorUser.GetDisplayName}}">{{- ctx.AvatarUtils.Avatar .AuthorUser 20 -}}</a>
+			{{- else -}}
+				{{- ctx.AvatarUtils.AvatarByEmail .AuthorSignature.Email .AuthorSignature.Name 20 -}}
+			{{- end -}}
+			{{- range $visibleCo -}}
+				{{- if .GiteaUser -}}
+					<a href="{{.GiteaUser.HomeLink}}" data-tooltip-content="{{.GiteaUser.GetDisplayName}}">{{- ctx.AvatarUtils.Avatar .GiteaUser 20 -}}</a>
+				{{- else -}}
+					{{- ctx.AvatarUtils.AvatarByEmail .TrailerSignature.Email .TrailerSignature.Name 20 -}}
+				{{- end -}}
+			{{- end -}}
+		</span>
+		{{- if gt $overflow 0 -}}
+			{{- $overflowLabel := ctx.Locale.TrN $overflow "repo.commits.coauthor_others_1" "repo.commits.coauthor_others_n" $overflow -}}
+			<span class="coauthor-overflow-chip" role="img" aria-label="{{$overflowLabel}}" data-tooltip-content="{{$overflowLabel}}">+{{$overflow}}</span>
+		{{- end -}}
+	</span>
+{{else if .AuthorUser}}
+	{{- ctx.AvatarUtils.Avatar .AuthorUser 20 .AdditionalClasses -}}
+{{else}}
+	{{- ctx.AvatarUtils.AvatarByEmail .AuthorSignature.Email .AuthorSignature.Name 20 .AdditionalClasses -}}
+{{end}}
diff --git a/templates/repo/commit_coauthor_avatars.tmpl b/templates/repo/commit_coauthor_avatars.tmpl
new file mode 100644
index 0000000000..a6b73de794
--- /dev/null
+++ b/templates/repo/commit_coauthor_avatars.tmpl
@@ -0,0 +1,44 @@
+{{/*
+	Renders the author/co-author avatar stack and name text for a commit.
+	Args (via dict):
+		AuthorUser       - *user_model.User (may be nil if no Gitea account)
+		AuthorSignature  - *git.Signature   (always set: name + email from git)
+		CoAuthors        - []*user_model.CoAuthorUser
+		fields: GiteaUser (*User, may be nil), TrailerSignature (*git.Signature)
+
+	Avatar stack is capped at 10 children (author + up to 9 co-authors); any
+	remainder is collapsed into a trailing "+N" chip. The .coauthor-avatar-stack
+	CSS rules expect at most 10 children to fan out cleanly on hover.
+*/}}
+<span class="author-wrapper">
+{{- if .CoAuthors -}}
+	{{- $coCount := len .CoAuthors -}}
+	{{template "repo/commit_coauthor_avatar_stack" dict "AuthorUser" .AuthorUser "AuthorSignature" .AuthorSignature "CoAuthors" .CoAuthors}}
+	{{- if .AuthorUser -}}
+		{{- .AuthorUser.GetShortDisplayNameLinkHTML -}}
+	{{- else -}}
+		{{.AuthorSignature.Name}}
+	{{- end -}}
+	{{" "}}{{ctx.Locale.Tr "repo.commits.coauthor_and"}}{{" "}}
+	{{- if eq $coCount 1 -}}
+		{{- with index .CoAuthors 0 -}}
+			{{- if .GiteaUser -}}
+				<a class="muted" href="{{.GiteaUser.HomeLink}}">{{.GiteaUser.GetDisplayName}}</a>
+			{{- else -}}
+				{{.TrailerSignature.Name}}
+			{{- end -}}
+		{{- end -}}
+	{{- else -}}
+		{{- $peopleCount := Eval $coCount "+" 1 -}}
+		{{- ctx.Locale.Tr "repo.commits.coauthor_people" $peopleCount -}}
+	{{- end -}}
+{{- else -}}
+	{{- if .AuthorUser -}}
+		{{- template "repo/commit_coauthor_avatar_stack" dict "AuthorUser" .AuthorUser "AuthorSignature" .AuthorSignature "AdditionalClasses" "tw-mr-1" -}}
+		{{- .AuthorUser.GetShortDisplayNameLinkHTML -}}
+	{{- else -}}
+		{{- template "repo/commit_coauthor_avatar_stack" dict "AuthorSignature" .AuthorSignature "AdditionalClasses" "tw-mr-1" -}}
+		{{.AuthorSignature.Name}}
+	{{- end -}}
+{{- end -}}
+</span>
diff --git a/templates/repo/commit_page.tmpl b/templates/repo/commit_page.tmpl
index 975cd303ec..cda0d29723 100644
--- a/templates/repo/commit_page.tmpl
+++ b/templates/repo/commit_page.tmpl
@@ -155,6 +155,21 @@
 				{{end}}
 			</div>
 
+			{{if .CoAuthors}}
+				<div class="flex-text-inline">
+					<span class="tw-text-text-light">{{ctx.Locale.Tr "repo.diff.coauthored_by"}}</span>
+					{{range .CoAuthors}}
+						{{if .GiteaUser}}
+							{{ctx.AvatarUtils.Avatar .GiteaUser 20}}
+							<a href="{{.GiteaUser.HomeLink}}"><strong>{{.GiteaUser.GetDisplayName}}</strong></a>
+						{{else}}
+							{{ctx.AvatarUtils.AvatarByEmail .TrailerSignature.Email .TrailerSignature.Name 20}}
+							<strong>{{.TrailerSignature.Name}}</strong>
+						{{end}}
+					{{end}}
+				</div>
+			{{end}}
+
 			{{if .Verification}}
 				{{template "repo/commit_sign_badge" dict "CommitSignVerification" .Verification}}
 			{{end}}
diff --git a/templates/repo/commit_sign_badge.tmpl b/templates/repo/commit_sign_badge.tmpl
index f63e4ec899..bf8185fd0b 100644
--- a/templates/repo/commit_sign_badge.tmpl
+++ b/templates/repo/commit_sign_badge.tmpl
@@ -64,10 +64,10 @@ so this template should be kept as small as possible, DO NOT put large component
 		{{- if $verified -}}
 			{{- if and $signingUser $signingUser.ID -}}
 				<span data-tooltip-content="{{$msgReason}}">{{svg "gitea-lock"}}</span>
-				<span data-tooltip-content="{{$msgSigningKey}}">{{ctx.AvatarUtils.Avatar $signingUser 16}}</span>
+				<span data-tooltip-content="{{$msgSigningKey}}">{{ctx.AvatarUtils.Avatar $signingUser 20}}</span>
 			{{- else -}}
 				<span data-tooltip-content="{{$msgReason}}">{{svg "gitea-lock-cog"}}</span>
-				<span data-tooltip-content="{{$msgSigningKey}}">{{ctx.AvatarUtils.AvatarByEmail $signingEmail "" 16}}</span>
+				<span data-tooltip-content="{{$msgSigningKey}}">{{ctx.AvatarUtils.AvatarByEmail $signingEmail "" 20}}</span>
 			{{- end -}}
 		{{- else -}}
 			<span data-tooltip-content="{{$msgReason}}">{{svg "gitea-unlock"}}</span>
diff --git a/templates/repo/commits_list.tmpl b/templates/repo/commits_list.tmpl
index e79d189b8d..e80b6cdc24 100644
--- a/templates/repo/commits_list.tmpl
+++ b/templates/repo/commits_list.tmpl
@@ -2,9 +2,9 @@
 	<table class="ui very basic table unstackable" id="commits-table">
 		<thead>
 			<tr>
-				<th class="three wide">{{ctx.Locale.Tr "repo.commits.author"}}</th>
+				<th class="four wide">{{ctx.Locale.Tr "repo.commits.author"}}</th>
 				<th class="two wide sha">{{StringUtils.ToUpper $.Repository.ObjectFormatName}}</th>
-				<th class="eight wide message">{{ctx.Locale.Tr "repo.commits.message"}}</th>
+				<th class="seven wide message">{{ctx.Locale.Tr "repo.commits.message"}}</th>
 				<th class="two wide tw-text-right">{{ctx.Locale.Tr "repo.commits.date"}}</th>
 				<th class="one wide"></th>
 			</tr>
@@ -14,15 +14,7 @@
 			{{range $commit := .Commits}}
 				<tr>
 					<td class="author">
-						<span class="author-wrapper">
-							{{- if .User -}}
-								{{- ctx.AvatarUtils.Avatar .User 20 "tw-mr-2" -}}
-								{{- .User.GetShortDisplayNameLinkHTML -}}
-							{{- else -}}
-								{{- ctx.AvatarUtils.AvatarByEmail .Author.Email .Author.Name 20 "tw-mr-2" -}}
-								{{- .Author.Name -}}
-							{{- end -}}
-						</span>
+						{{template "repo/commit_coauthor_avatars" dict "AuthorUser" .User "AuthorSignature" .Author "CoAuthors" .CoAuthors}}
 					</td>
 					<td class="sha">
 						{{$commitBaseLink := ""}}
diff --git a/templates/repo/commits_list_small.tmpl b/templates/repo/commits_list_small.tmpl
index c5f0d5b590..c1cadf74ba 100644
--- a/templates/repo/commits_list_small.tmpl
+++ b/templates/repo/commits_list_small.tmpl
@@ -5,11 +5,7 @@
 	{{$index = Eval $index "+" 1}}
 	<div class="flex-text-block" id="{{$tag}}">{{/*singular-commit*/}}
 		<span class="badge badge-commit">{{svg "octicon-git-commit"}}</span>
-		{{if .User}}
-			<a class="avatar" href="{{.User.HomeLink}}">{{ctx.AvatarUtils.Avatar .User 20}}</a>
-		{{else}}
-			{{ctx.AvatarUtils.AvatarByEmail .Author.Email .Author.Name 20}}
-		{{end}}
+		{{template "repo/commit_coauthor_avatar_stack" dict "AuthorUser" .User "AuthorSignature" .Author "CoAuthors" .CoAuthors}}
 
 		{{$commitBaseLink := printf "%s/commit" $.comment.Issue.PullRequest.BaseRepo.Link}}
 		{{$commitLink:= printf "%s/%s" $commitBaseLink (PathEscape .ID.String)}}
diff --git a/templates/repo/graph/commits.tmpl b/templates/repo/graph/commits.tmpl
index d86f73fe65..7b834d2be7 100644
--- a/templates/repo/graph/commits.tmpl
+++ b/templates/repo/graph/commits.tmpl
@@ -41,14 +41,7 @@
 					</span>
 
 					<span class="flex-text-inline tw-text-12">
-						{{if $commit.User}}
-							{{ctx.AvatarUtils.Avatar $commit.User 18}}
-							{{$commit.User.GetShortDisplayNameLinkHTML}}
-						{{else}}
-							{{$gitUserName := $commit.Commit.Author.Name}}
-							{{ctx.AvatarUtils.AvatarByEmail $commit.Commit.Author.Email $gitUserName 18}}
-							{{$gitUserName}}
-						{{end}}
+						{{template "repo/commit_coauthor_avatars" dict "AuthorUser" $commit.User "AuthorSignature" $commit.Commit.Author "CoAuthors" $commit.CoAuthors}}
 					</span>
 
 					<span class="time flex-text-inline">{{DateUtils.FullTime $commit.Date}}</span>
diff --git a/templates/repo/latest_commit.tmpl b/templates/repo/latest_commit.tmpl
index c0518189b8..3a3b162ba5 100644
--- a/templates/repo/latest_commit.tmpl
+++ b/templates/repo/latest_commit.tmpl
@@ -2,15 +2,7 @@
 {{if not .LatestCommit}}
 	…
 {{else}}
-	<span class="author-wrapper">
-	{{- if .LatestCommitUser -}}
-		{{- ctx.AvatarUtils.Avatar .LatestCommitUser 20 "tw-mr-2" -}}
-		<strong>{{.LatestCommitUser.GetShortDisplayNameLinkHTML}}</strong>
-	{{- else if .LatestCommit.Author -}}
-		{{- ctx.AvatarUtils.AvatarByEmail .LatestCommit.Author.Email .LatestCommit.Author.Name 20 "tw-mr-2" -}}
-		<strong>{{.LatestCommit.Author.Name}}</strong>
-	{{- end -}}
-	</span>
+	{{template "repo/commit_coauthor_avatars" dict "AuthorUser" .LatestCommitUser "AuthorSignature" .LatestCommit.Author "CoAuthors" .LatestCommitCoAuthors}}
 
 	{{template "repo/commit_sign_badge" dict "Commit" .LatestCommit "CommitBaseLink" (print .RepoLink "/commit") "CommitSignVerification" .LatestCommitVerification}}
 
diff --git a/templates/user/dashboard/feeds.tmpl b/templates/user/dashboard/feeds.tmpl
index baf077863c..0981fea8f1 100644
--- a/templates/user/dashboard/feeds.tmpl
+++ b/templates/user/dashboard/feeds.tmpl
@@ -91,7 +91,7 @@
 						{{range $pushCommit := $push.Commits}}
 							{{$commitLink := printf "%s/commit/%s" $repoLink .Sha1}}
 							<div class="flex-text-block">
-								<img loading="lazy" alt class="ui avatar" src="{{$push.AvatarLink ctx .AuthorEmail}}" title="{{.AuthorName}}" width="16" height="16">
+								{{template "repo/commit_coauthor_avatar_stack" dict "AuthorSignature" .AuthorSignature "CoAuthors" .CoAuthorUsers}}
 								<a class="ui sha label" href="{{$commitLink}}">{{ShortSha .Sha1}}</a>
 								<span class="tw-inline-block tw-truncate">
 									{{ctx.RenderUtils.RenderCommitMessage $pushCommit.Message $repo}}
diff --git a/web_src/css/repo.css b/web_src/css/repo.css
index 3eb016650f..0a30cf6ce5 100644
--- a/web_src/css/repo.css
+++ b/web_src/css/repo.css
@@ -1403,11 +1403,77 @@ tbody.commit-list {
 }
 
 .author-wrapper {
-  max-width: 180px;
+  max-width: 240px;
   align-self: center;
   white-space: nowrap;
 }
 
+.coauthor-avatar-stack-wrapper {
+  display: inline-flex;
+  align-items: center;
+  vertical-align: middle;
+  margin-right: 0.25rem;
+}
+
+.coauthor-avatar-stack {
+  display: inline-flex;
+  align-items: center;
+}
+
+/* each direct child of the stack is either <a> (linked user) or <img> (no account) */
+.coauthor-avatar-stack > * {
+  margin-left: -12px;
+  transition: transform 0.15s ease;
+  position: relative;
+  z-index: 0;
+  display: inline-flex;
+  border-radius: 50%;
+}
+
+.coauthor-avatar-stack > *:first-child {
+  margin-left: 0;
+}
+
+.coauthor-avatar-stack .avatar {
+  border: 2px solid var(--color-body);
+  border-radius: 50%;
+}
+
+.coauthor-overflow-chip {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 20px;
+  height: 20px;
+  font-size: 10px;
+  font-weight: var(--font-weight-semibold);
+  border: 2px solid var(--color-body);
+  border-radius: 50%;
+  background: var(--color-secondary);
+  color: var(--color-text);
+}
+
+.coauthor-avatar-stack > *:nth-child(1) { z-index: 20; }
+.coauthor-avatar-stack > *:nth-child(2) { z-index: 19; }
+.coauthor-avatar-stack > *:nth-child(3) { z-index: 18; }
+.coauthor-avatar-stack > *:nth-child(4) { z-index: 17; }
+.coauthor-avatar-stack > *:nth-child(5) { z-index: 16; }
+.coauthor-avatar-stack > *:nth-child(6) { z-index: 15; }
+.coauthor-avatar-stack > *:nth-child(7) { z-index: 14; }
+.coauthor-avatar-stack > *:nth-child(8) { z-index: 13; }
+.coauthor-avatar-stack > *:nth-child(9) { z-index: 12; }
+.coauthor-avatar-stack > *:nth-child(10) { z-index: 11; }
+
+.coauthor-avatar-stack:hover > *:nth-child(2) { transform: translateX(12px); }
+.coauthor-avatar-stack:hover > *:nth-child(3) { transform: translateX(24px); }
+.coauthor-avatar-stack:hover > *:nth-child(4) { transform: translateX(36px); }
+.coauthor-avatar-stack:hover > *:nth-child(5) { transform: translateX(48px); }
+.coauthor-avatar-stack:hover > *:nth-child(6) { transform: translateX(60px); }
+.coauthor-avatar-stack:hover > *:nth-child(7) { transform: translateX(72px); }
+.coauthor-avatar-stack:hover > *:nth-child(8) { transform: translateX(84px); }
+.coauthor-avatar-stack:hover > *:nth-child(9) { transform: translateX(96px); }
+.coauthor-avatar-stack:hover > *:nth-child(10) { transform: translateX(108px); }
+
 .latest-commit .message-wrapper {
   max-width: calc(100% - 2.5rem);
 }