diff --git a/services/repository/contributors_graph.go b/services/repository/contributors_graph.go
index 41c9c4f8ab..fa2d2360ec 100644
--- a/services/repository/contributors_graph.go
+++ b/services/repository/contributors_graph.go
@@ -161,6 +161,10 @@ func getExtendedCommitStats(repo *git.Repository, revision string /*, limit int
 						break
 					}
 					coAuthorName, coAuthorEmail, err := util.ParseCommitTrailerValueWithAuthor(line)
+					if authorEmail == coAuthorEmail {
+						// Authors shouldn't be co-authors too.
+						continue
+					}
 					if err != nil {
 						continue
 					}
diff --git a/tests/gitea-repositories-meta/user2/repo2.git/objects/ab/60139e57bea4f9dc090a72cf97b7236d152a4b b/tests/gitea-repositories-meta/user2/repo2.git/objects/ab/60139e57bea4f9dc090a72cf97b7236d152a4b
new file mode 100644
index 0000000000..5c4919fb1b
Binary files /dev/null and b/tests/gitea-repositories-meta/user2/repo2.git/objects/ab/60139e57bea4f9dc090a72cf97b7236d152a4b differ
diff --git a/tests/gitea-repositories-meta/user2/repo2.git/objects/f7/eee4e802f39ec0dadc5f872c86d4ee440b741d b/tests/gitea-repositories-meta/user2/repo2.git/objects/f7/eee4e802f39ec0dadc5f872c86d4ee440b741d
new file mode 100644
index 0000000000..1e3c7faf58
Binary files /dev/null and b/tests/gitea-repositories-meta/user2/repo2.git/objects/f7/eee4e802f39ec0dadc5f872c86d4ee440b741d differ
diff --git a/tests/gitea-repositories-meta/user2/repo2.git/refs/heads/branch-with-duplicated-co-author-entries b/tests/gitea-repositories-meta/user2/repo2.git/refs/heads/branch-with-duplicated-co-author-entries
index c17567e1fb..f8c5eee90d 100644
--- a/tests/gitea-repositories-meta/user2/repo2.git/refs/heads/branch-with-duplicated-co-author-entries
+++ b/tests/gitea-repositories-meta/user2/repo2.git/refs/heads/branch-with-duplicated-co-author-entries
@@ -1 +1 @@
-79a64f10ca2ea21fa2a94102751f0dd9f2c15ce8
+f7eee4e802f39ec0dadc5f872c86d4ee440b741d