diff --git a/git.py b/git.py
index bf30e83..8402c8c 100644
--- a/git.py
+++ b/git.py
@@ -223,6 +223,17 @@ class Repo:
         refs = self._for_each_ref(pattern="refs/heads/", sort="-authordate")
         return [ref[len("refs/heads/") :] for _, _, ref in refs]
 
+    @functools.cache
+    def main_branch(self):
+        """Get the name of the main branch."""
+        bs = self.branch_names()
+        for branch in ["master", "main"]:
+            if branch in bs:
+                return branch
+        if bs:
+            return bs[0]
+        return None
+
     @functools.cache
     def tags(self, sort="-taggerdate"):
         """Get the (name, obj_id) of the tags."""
diff --git a/views/summary.html b/views/summary.html
index d3388e6..9b180b8 100644
--- a/views/summary.html
+++ b/views/summary.html
@@ -35,20 +35,22 @@
 <hr/>
 % end
 
-% if "master" in repo.branch_names():
+% if repo.main_branch():
 <div class="toggable-title" onclick="toggle('commits')">
-  <a href="b/master/">commits (master)</a>
+  <a href="b/{{repo.main_branch()}}/">commits ({{repo.main_branch()}})</a>
 </div>
-%     kwargs = dict(repo = repo, start_ref = "refs/heads/master",
+%     kwargs = dict(repo = repo,
+%                   start_ref = "refs/heads/" + repo.main_branch(),
 %                   limit = repo.info.commits_in_summary,
 %                   shorten = shorten, repo_root = ".", offset = 0)
 %     include commit-list **kwargs
 <hr/>
 <div class="toggable-title" onclick="toggle('ls')">
-  <a href="b/master/t/">tree (master)</a>
+  <a href="b/{{repo.main_branch()}}/t/">tree ({{repo.main_branch()}})</a>
 </div>
-%     kwargs = dict(repo = repo, tree=repo.tree("master"),
-%                   treeroot="b/master/t", dirname=smstr.from_url(""))
+%     kwargs = dict(repo = repo, tree=repo.tree(repo.main_branch()),
+%                   treeroot="b/" + repo.main_branch() + "/t",
+%                   dirname=smstr.from_url(""))
 %     include tree-list **kwargs
 <hr/>
 % end