diff --git a/jeepyb/utils.py b/jeepyb/utils.py
index a0be878..8d726e6 100644
--- a/jeepyb/utils.py
+++ b/jeepyb/utils.py
@@ -88,9 +88,14 @@
 def make_ssh_wrapper(gerrit_user, gerrit_key):
     (fd, name) = tempfile.mkstemp(text=True)
     os.write(fd, b'#!/bin/bash\n')
-    os.write(fd,
-             b'ssh -i %s -l %s -o "StrictHostKeyChecking no" $@\n' %
-             (gerrit_key.encode('utf-8'), gerrit_user.encode('utf-8')))
+    if gerrit_key is None:
+        os.write(fd,
+                 b'ssh -l %s -o "StrictHostKeyChecking no" $@\n' %
+                 (gerrit_user.encode('utf-8')))
+    else:
+        os.write(fd,
+                 b'ssh -i %s -l %s -o "StrictHostKeyChecking no" $@\n' %
+                 (gerrit_key.encode('utf-8'), gerrit_user.encode('utf-8')))
     os.close(fd)
     os.chmod(name, 0o755)
     return dict(GIT_SSH=name)