diff --git a/core/modules/system/templates/menu.html.twig b/core/modules/system/templates/menu.html.twig
index 03704f2..389e9aa 100644
--- a/core/modules/system/templates/menu.html.twig
+++ b/core/modules/system/templates/menu.html.twig
@@ -30,20 +30,22 @@
 
 {% macro menu_links(items, attributes, menu_level) %}
   {% import _self as menus %}
-  {% if items %}
-    {% if menu_level == 0 %}
-      <ul{{ attributes }}>
-    {% else %}
-      <ul>
-    {% endif %}
-    {% for item in items %}
-      <li{{ item.attributes }}>
-        {{ link(item.title, item.url) }}
-        {% if item.below %}
-          {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+  {% for item in items %}
+    {% if loop.first %}
+      <ul {% spaceless %}
+        {% if menu_level == 0 %}
+          {{ attributes }}
         {% endif %}
-      </li>
-    {% endfor %}
-    </ul>
-  {% endif %}
+      {% endspaceless %}>
+    {% endif %}
+    <li{{ item.attributes }}>
+      {{ link(item.title, item.url) }}
+      {% if item.below %}
+        {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+      {% endif %}
+    </li>
+    {% if loop.last %}
+      </ul>
+    {% endif %}
+  {% endfor %}
 {% endmacro %}
diff --git a/core/modules/toolbar/templates/menu--toolbar.html.twig b/core/modules/toolbar/templates/menu--toolbar.html.twig
index 659e8f5..ce0d92e 100644
--- a/core/modules/toolbar/templates/menu--toolbar.html.twig
+++ b/core/modules/toolbar/templates/menu--toolbar.html.twig
@@ -30,28 +30,32 @@
 
 {% macro menu_links(items, attributes, menu_level) %}
   {% import _self as menus %}
-  {% if items %}
-    {% if menu_level == 0 %}
-      <ul{{ attributes.addClass('toolbar-menu') }}>
-    {% else %}
-      <ul class="toolbar-menu">
-    {% endif %}
-    {% for item in items %}
-      {%
-        set classes = [
-          'menu-item',
-          item.is_expanded ? 'menu-item--expanded',
-          item.is_collapsed ? 'menu-item--collapsed',
-          item.in_active_trail ? 'menu-item--active-trail',
-        ]
-      %}
-      <li{{ item.attributes.addClass(classes) }}>
-        {{ link(item.title, item.url) }}
-        {% if item.below %}
-          {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+  {% for item in items %}
+    {% if loop.first %}
+      <ul {% spaceless %}
+        {% if menu_level == 0 %}
+          {{ attributes.addClass('toolbar-menu') }}
+        {% else %}
+          class="toolbar-menu"
         {% endif %}
-      </li>
-    {% endfor %}
-    </ul>
-  {% endif %}
+      {% endspaceless %}>
+    {% endif %}
+    {%
+      set classes = [
+        'menu-item',
+        item.is_expanded ? 'menu-item--expanded',
+        item.is_collapsed ? 'menu-item--collapsed',
+        item.in_active_trail ? 'menu-item--active-trail',
+      ]
+    %}
+    <li{{ item.attributes.addClass(classes) }}>
+      {{ link(item.title, item.url) }}
+      {% if item.below %}
+        {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+      {% endif %}
+    </li>
+    {% if loop.last %}
+      </ul>
+    {% endif %}
+  {% endfor %}
 {% endmacro %}
diff --git a/core/themes/classy/templates/navigation/menu.html.twig b/core/themes/classy/templates/navigation/menu.html.twig
index e482ef4..3f73bc1 100644
--- a/core/themes/classy/templates/navigation/menu.html.twig
+++ b/core/themes/classy/templates/navigation/menu.html.twig
@@ -28,28 +28,32 @@
 
 {% macro menu_links(items, attributes, menu_level) %}
   {% import _self as menus %}
-  {% if items %}
-    {% if menu_level == 0 %}
-      <ul{{ attributes.addClass('menu') }}>
-    {% else %}
-      <ul class="menu">
-    {% endif %}
-    {% for item in items %}
-      {%
-        set classes = [
-          'menu-item',
-          item.is_expanded ? 'menu-item--expanded',
-          item.is_collapsed ? 'menu-item--collapsed',
-          item.in_active_trail ? 'menu-item--active-trail',
-        ]
-      %}
-      <li{{ item.attributes.addClass(classes) }}>
-        {{ link(item.title, item.url) }}
-        {% if item.below %}
-          {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+  {% for item in items %}
+    {% if loop.first %}
+      <ul {% spaceless %}
+        {% if menu_level == 0 %}
+          {{ attributes.addClass('menu') }}
+        {% else %}
+          class="menu"
         {% endif %}
-      </li>
-    {% endfor %}
-    </ul>
-  {% endif %}
+      {% endspaceless %}>
+    {% endif %}
+    {%
+      set classes = [
+        'menu-item',
+        item.is_expanded ? 'menu-item--expanded',
+        item.is_collapsed ? 'menu-item--collapsed',
+        item.in_active_trail ? 'menu-item--active-trail',
+      ]
+    %}
+    <li{{ item.attributes.addClass(classes) }}>
+      {{ link(item.title, item.url) }}
+      {% if item.below %}
+        {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+      {% endif %}
+    </li>
+    {% if loop.last %}
+      </ul>
+    {% endif %}
+  {% endfor %}
 {% endmacro %}
diff --git a/core/themes/stable/templates/navigation/menu--toolbar.html.twig b/core/themes/stable/templates/navigation/menu--toolbar.html.twig
index 55cfc5b..215bba9 100644
--- a/core/themes/stable/templates/navigation/menu--toolbar.html.twig
+++ b/core/themes/stable/templates/navigation/menu--toolbar.html.twig
@@ -28,28 +28,32 @@
 
 {% macro menu_links(items, attributes, menu_level) %}
   {% import _self as menus %}
-  {% if items %}
-    {% if menu_level == 0 %}
-      <ul{{ attributes.addClass('toolbar-menu') }}>
-    {% else %}
-      <ul class="toolbar-menu">
-    {% endif %}
-    {% for item in items %}
-      {%
-        set classes = [
-          'menu-item',
-          item.is_expanded ? 'menu-item--expanded',
-          item.is_collapsed ? 'menu-item--collapsed',
-          item.in_active_trail ? 'menu-item--active-trail',
-        ]
-      %}
-      <li{{ item.attributes.addClass(classes) }}>
-        {{ link(item.title, item.url) }}
-        {% if item.below %}
-          {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+  {% for item in items %}
+    {% if loop.first %}
+      <ul {% spaceless %}
+        {% if menu_level == 0 %}
+          {{ attributes.addClass('toolbar-menu') }}
+        {% else %}
+          class="toolbar-menu"
         {% endif %}
-      </li>
-    {% endfor %}
-    </ul>
-  {% endif %}
+      {% endspaceless %}>
+    {% endif %}
+    {%
+      set classes = [
+        'menu-item',
+        item.is_expanded ? 'menu-item--expanded',
+        item.is_collapsed ? 'menu-item--collapsed',
+        item.in_active_trail ? 'menu-item--active-trail',
+      ]
+    %}
+    <li{{ item.attributes.addClass(classes) }}>
+      {{ link(item.title, item.url) }}
+      {% if item.below %}
+        {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+      {% endif %}
+    </li>
+    {% if loop.last %}
+      </ul>
+    {% endif %}
+  {% endfor %}
 {% endmacro %}
diff --git a/core/themes/stable/templates/navigation/menu.html.twig b/core/themes/stable/templates/navigation/menu.html.twig
index 33efca8..389e9aa 100644
--- a/core/themes/stable/templates/navigation/menu.html.twig
+++ b/core/themes/stable/templates/navigation/menu.html.twig
@@ -1,7 +1,7 @@
 {#
 /**
  * @file
- * Theme override to display a menu.
+ * Default theme implementation to display a menu.
  *
  * Available variables:
  * - menu_name: The machine name of the menu.
@@ -16,6 +16,8 @@
  *   - is_collapsed: TRUE if the link has children within the current menu tree
  *     that are not currently visible.
  *   - in_active_trail: TRUE if the link is in the active trail.
+ *
+ * @ingroup themeable
  */
 #}
 {% import _self as menus %}
@@ -28,20 +30,22 @@
 
 {% macro menu_links(items, attributes, menu_level) %}
   {% import _self as menus %}
-  {% if items %}
-    {% if menu_level == 0 %}
-      <ul{{ attributes }}>
-    {% else %}
-      <ul>
-    {% endif %}
-    {% for item in items %}
-      <li{{ item.attributes }}>
-        {{ link(item.title, item.url) }}
-        {% if item.below %}
-          {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+  {% for item in items %}
+    {% if loop.first %}
+      <ul {% spaceless %}
+        {% if menu_level == 0 %}
+          {{ attributes }}
         {% endif %}
-      </li>
-    {% endfor %}
-    </ul>
-  {% endif %}
+      {% endspaceless %}>
+    {% endif %}
+    <li{{ item.attributes }}>
+      {{ link(item.title, item.url) }}
+      {% if item.below %}
+        {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
+      {% endif %}
+    </li>
+    {% if loop.last %}
+      </ul>
+    {% endif %}
+  {% endfor %}
 {% endmacro %}