diff --git a/lib/gitlab/o_auth/user.rb b/lib/gitlab/o_auth/user.rb
index 0a91d3918d553baaa0ef6bdb7f48b65651ac824e..e4e6f36613f6cb091373cca8c30bba3c68703031 100644
--- a/lib/gitlab/o_auth/user.rb
+++ b/lib/gitlab/o_auth/user.rb
@@ -102,6 +102,10 @@ def ldap_person
         Gitlab::LDAP::Config.providers.each do |provider|
           adapter = Gitlab::LDAP::Adapter.new(provider)
           @ldap_person = Gitlab::LDAP::Person.find_by_uid(auth_hash.uid, adapter)
+          # The `uid` might actually be a DN. Try it next.
+          unless @ldap_person
+            @ldap_person = Gitlab::LDAP::Person.find_by_dn(auth_hash.uid, adapter)
+          end
           break if @ldap_person
         end
         @ldap_person