diff --git a/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host.js b/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host.js
index d3ad997..497ea9c 100644
--- a/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host.js
+++ b/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host.js
@@ -34,11 +34,13 @@
       const jsPlugins = this._handleMigrations(plugins.js_resource_paths || [],
           htmlPlugins);
       const defaultTheme = config.default_theme;
+      Gerrit._setPluginsCount(
+          jsPlugins.length + htmlPlugins.length + (defaultTheme ? 1 : 0));
       if (defaultTheme) {
         // Make theme first to be first to load.
-        htmlPlugins.unshift(defaultTheme);
+        // Load sync to work around rare theme loading race condition.
+        this._importHtmlPlugins([defaultTheme], true);
       }
-      Gerrit._setPluginsCount(jsPlugins.length + htmlPlugins.length);
       this._loadJsPlugins(jsPlugins);
       this._importHtmlPlugins(htmlPlugins);
     },
@@ -58,13 +60,16 @@
      * @suppress {checkTypes}
      * States that it expects no more than 3 parameters, but that's not true.
      * @todo (beckysiegel) check Polymer annotations and submit change.
+     * @param {Array} plugins
+     * @param {boolean=} opt_sync
      */
-    _importHtmlPlugins(plugins) {
+    _importHtmlPlugins(plugins, opt_sync) {
+      const async = !opt_sync;
       for (const url of plugins) {
         // onload (second param) needs to be a function. When null or undefined
         // were passed, plugins were not loaded correctly.
         this.importHref(
-            this._urlFor(url), () => {}, Gerrit._pluginInstalled, true);
+            this._urlFor(url), () => {}, Gerrit._pluginInstalled, async);
       }
     },
 
diff --git a/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host_test.html b/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host_test.html
index dd664ff..d42cb88 100644
--- a/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host_test.html
+++ b/polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host_test.html
@@ -164,7 +164,7 @@
       assert.equal(element.importHref.firstCall.args[0], '/oof');
       assert.equal(element.importHref.firstCall.args[2],
           Gerrit._pluginInstalled);
-      assert.isTrue(element.importHref.firstCall.args[3]);
+      assert.isFalse(element.importHref.firstCall.args[3]);
 
       assert.equal(element.importHref.secondCall.args[0], '/some');
       assert.equal(element.importHref.secondCall.args[2],