diff --git a/core/themes/classy/templates/form/select.html.twig b/core/themes/classy/templates/form/select.html.twig
new file mode 100644
index 0000000..3150bdc
--- /dev/null
+++ b/core/themes/classy/templates/form/select.html.twig
@@ -0,0 +1,27 @@
+{#
+/**
+ * @file
+ * Theme override for a select element.
+ *
+ * Available variables:
+ * - attributes: HTML attributes for the select tag.
+ * - options: The option element children.
+ *
+ * @see template_preprocess_select()
+ */
+#}
+{% spaceless %}
+  <select{{ attributes }}>
+    {% for option in options %}
+      {% if option.type == 'optgroup' %}
+        <optgroup label="{{ option.label }}">
+          {% for sub_option in option.options %}
+            <option value="{{ sub_option.value }}"{{ sub_option.selected ? ' selected="selected"' }}>{{ sub_option.label }}</option>
+          {% endfor %}
+        </optgroup>
+      {% elseif option.type == 'option' %}
+        <option value="{{ option.value }}"{{ option.selected ? ' selected="selected"' }}>{{ option.label }}</option>
+      {% endif %}
+    {% endfor %}
+  </select>
+{% endspaceless %}