diff --git a/module_build_service/builder/MockModuleBuilder.py b/module_build_service/builder/MockModuleBuilder.py
index 8f2461df..7611f103 100644
--- a/module_build_service/builder/MockModuleBuilder.py
+++ b/module_build_service/builder/MockModuleBuilder.py
@@ -316,13 +316,16 @@ class MockModuleBuilder(GenericBuilder):
                 koji_session = koji.ClientSession(koji_config.server, opts=koji_config)
                 repo = koji_session.getRepo(repo_name)
                 if repo:
-                    baseurl = koji.PathInfo(topdir=koji_config.topurl).repo(repo['id'], repo_name)
+                    baseurl = koji.PathInfo(topdir=koji_config.topurl).repo(repo["id"], repo_name)
                     baseurl = '{0}/{1}/'.format(baseurl, self.arch)
                 else:
                     repo_dir = os.path.join(self.config.cache_dir, "koji_tags", tag)
                     create_local_repo_from_koji_tag(self.config, tag, repo_dir,
                                                     [self.arch, "noarch"])
                     baseurl = "file://" + repo_dir
+                # Check to see if there are any external repos tied to the tag
+                for ext_repo in koji_session.getTagExternalRepos(repo_name):
+                    self._add_repo(ext_repo["external_repo_name"], ext_repo["url"])
             self._add_repo(repo_name, baseurl)
         self._write_mock_config()