diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index b21bfb1..8a77595 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1464,6 +1464,7 @@ function drupal_pre_render_table(array $element) {
  *     can be either a localized string or an associative array with the
  *     following keys:
  *     - "data": The localized summary information of the table column.
+ *     - "header": Indicates this cell is a header.
  *     - Any HTML attributes, such as "colspan", to apply to the column footer
  *       cell.
  *   - attributes: An array of HTML attributes to apply to the table tag.
@@ -1618,8 +1619,9 @@ function template_preprocess_table(&$variables) {
           $cell_content = $cell['data'];
           unset($cell['data']);
         }
-        // Flag the cell as a footer or not and remove the flag.
-        unset($cell['footer']);
+        // Flag the cell as a header or not and remove the flag.
+        $is_header = isset($cell['header']) ? $cell['header'] : TRUE;
+        unset($cell['header']);
 
         // Track responsive classes for each column as needed. Only the footer
         // cells for a column are marked up with the responsive classes by a
@@ -1640,7 +1642,7 @@ function template_preprocess_table(&$variables) {
         $cell_attributes = new Attribute($cell);
       }
       $variables['footer'][$col_key] = array();
-      $variables['footer'][$col_key]['tag'] = 'td';
+      $variables['header'][$col_key]['tag'] = $is_header ? 'th' : 'td';
       $variables['footer'][$col_key]['attributes'] = $cell_attributes;
       $variables['footer'][$col_key]['content'] = $cell_content;
     }
diff --git a/core/modules/system/templates/table.html.twig b/core/modules/system/templates/table.html.twig
index 4881e46..884349a 100644
--- a/core/modules/system/templates/table.html.twig
+++ b/core/modules/system/templates/table.html.twig
@@ -17,10 +17,6 @@
  *   - content: A localized string for the title of the column.
  *   - field: Field name (required for column sorting).
  *   - sort: Default sort order for this column ("asc" or "desc").
- * - header: Table header cells. Each cell contains the following properties:
- *   - attributes: HTML attributes to apply to the tag.
- *   - content: A localized string for the title of the column.
- *   - field: Field name (required for column sorting).
  * - sticky: A flag indicating whether to use a "sticky" table header.
  * - rows: Table rows. Each row contains the following properties:
  *   - attributes: HTML attributes to apply to the <tr> tag.
@@ -32,6 +28,11 @@
  *     - attributes: Any HTML attributes, such as "colspan", to apply to the
  *       table cell.
  *     - content: The string to display in the table cell.
+ * - footer: Table footer cells. Each cell contains the following properties:
+ *   - tag: The HTML tag name to use; either TH or TD.
+ *   - attributes: HTML attributes to apply to the tag.
+ *   - content: A localized string for the title of the column.
+ *   - field: Field name (required for column sorting).
  * - empty: The message to display in an extra row if table does not have
  *   any rows.
  *
@@ -66,17 +67,6 @@
       </tr>
     </thead>
   {% endif %}
-  {% if footer %}
-    <tfoot>
-    <tr>
-      {% for cell in footer %}
-        <td{{ cell.attributes }}>
-          {{- cell.content -}}
-        </td>
-      {% endfor %}
-    </tr>
-    </tfoot>
-  {% endif %}
   {% if rows %}
     <tbody>
       {% for row in rows %}
@@ -90,4 +80,15 @@
       {% endfor %}
     </tbody>
   {% endif %}
+  {% if footer %}
+    <tfoot>
+      <tr>
+        {% for cell in footer %}
+          <{{ cell.tag }}{{ cell.attributes }}>
+            {{- cell.content -}}
+          </{{ cell.tag }}>
+        {% endfor %}
+      </tr>
+    </tfoot>
+  {% endif %}
 </table>