diff --git a/core/modules/layout/layouts/static/one-col/one-col.html.twig b/core/modules/layout/layouts/static/one-col/one-col.html.twig
new file mode 100644
index 0000000000000000000000000000000000000000..8f30223b50c720b74128f1e56bf437f5c3991509
--- /dev/null
+++ b/core/modules/layout/layouts/static/one-col/one-col.html.twig
@@ -0,0 +1,21 @@
+{#
+/**
+ * @file
+ * Template for a 1 column layout.
+ *
+ * This template provides a simple one column display layout.
+ *
+ * Avaiable variables:
+ * - attributes: Attributes to be placed on the wrapping element.
+ * - content: All content items, each content item is keyed to one region of the
+ *   layout. 'content' contains the following section:
+ *   - content: Content in the content column.
+ *
+ * @ingroup themeable
+ */
+#}
+<div class="layout-display layout-one-col {{ attributes.class }}"{{ attributes }}>
+  <div class="layout-region">
+    {{ content.content }}
+  </div>
+</div>
diff --git a/core/modules/layout/layouts/static/one-col/one-col.tpl.php b/core/modules/layout/layouts/static/one-col/one-col.tpl.php
deleted file mode 100644
index 61af8327956fe0d61db10e2da41bd996bf649922..0000000000000000000000000000000000000000
--- a/core/modules/layout/layouts/static/one-col/one-col.tpl.php
+++ /dev/null
@@ -1,18 +0,0 @@
-<?php
-/**
- * @file
- * Template for a 1 column layout.
- *
- * This template provides a simple one column display layout.
- *
- * Variables:
- * - $content: An array of content, each item in the array is keyed to one
- *   region of the layout. This layout supports only one section:
- *   - $content['content']: Content in the content column.
- */
-?>
-<div class="layout-display layout-one-col <?php print $attributes['class']; ?>"<?php print $attributes; ?>>
-  <div class="layout-region">
-    <?php print $content['content']; ?>
-  </div>
-</div>
diff --git a/core/modules/layout/layouts/static/twocol/two-col.html.twig b/core/modules/layout/layouts/static/twocol/two-col.html.twig
new file mode 100644
index 0000000000000000000000000000000000000000..2bfade0a6a31cad1064a2dc3ac9a7cdc9af518fc
--- /dev/null
+++ b/core/modules/layout/layouts/static/twocol/two-col.html.twig
@@ -0,0 +1,27 @@
+{#
+/**
+ * @file
+ * Template for a 2 column layout.
+ *
+ * This template provides a two column display layout, with each column equal in
+ * width.
+ *
+ * Available variables:
+ * - attributes: Attributes to be placed on the wrapping element.
+ * - content: All content items, each content item is keyed to one region of the
+ *   layout. 'content' contains the following sections:
+ *   - first: Content in the first column.
+ *   - second: Content in the second column.
+ *
+ * @ingroup themeable
+ */
+#}
+<div class="layout-display layout-two-col clearfix {{ attributes.class }}"{{ attributes }}>
+  <div class="layout-region layout-col-first">
+    {{ content.first }}
+  </div>
+
+  <div class="layout-region layout-col-second">
+    {{ content.second }}
+  </div>
+</div>
diff --git a/core/modules/layout/layouts/static/twocol/two-col.tpl.php b/core/modules/layout/layouts/static/twocol/two-col.tpl.php
deleted file mode 100644
index 810a052b2c18d0860eeea6c93b1625c52c8ef10e..0000000000000000000000000000000000000000
--- a/core/modules/layout/layouts/static/twocol/two-col.tpl.php
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-/**
- * @file
- * Template for a 2 column layout.
- *
- * This template provides a two column display layout, with each column equal in
- * width.
- *
- * Variables:
- * - $content: An array of content, each item in the array is keyed to one
- *   region of the layout. This layout supports the following sections:
- *   - $content['first']: Content in the first column.
- *   - $content['second']: Content in the second column.
- */
-?>
-<div class="layout-display layout-two-col clearfix <?php print $attributes['class']; ?>"<?php print $attributes; ?>>
-  <div class="layout-region layout-col-first">
-    <?php print $content['first']; ?>
-  </div>
-
-  <div class="layout-region layout-col-second">
-    <?php print $content['second']; ?>
-  </div>
-</div>
diff --git a/core/modules/layout/tests/layouts/static/one-col/one-col.html.twig b/core/modules/layout/tests/layouts/static/one-col/one-col.html.twig
new file mode 100644
index 0000000000000000000000000000000000000000..c4f263d3ff046576cebab15fc4ceba3ebec92d46
--- /dev/null
+++ b/core/modules/layout/tests/layouts/static/one-col/one-col.html.twig
@@ -0,0 +1,20 @@
+{#
+/**
+ * @file
+ * Template for a one column layout.
+ *
+ * This template provides a very simple "one column" display layout.
+ *
+ * Avaiable variables:
+ * - content: All content items, each content item is keyed to one region of the
+ *   layout. 'content' contains the following section:
+ *   - middle: The only region in the layout.
+ *
+ * @ingroup themeable
+ */
+#}
+<div class="layout-display layout-one-col clearfix">
+  <div class="layout-region layout-col">
+    <div class="inside">{{ content.middle }}</div>
+  </div>
+</div>
diff --git a/core/modules/layout/tests/layouts/static/one-col/one-col.tpl.php b/core/modules/layout/tests/layouts/static/one-col/one-col.tpl.php
deleted file mode 100644
index e47f83ec473aba196cdd41689f7d74ac20db6b32..0000000000000000000000000000000000000000
--- a/core/modules/layout/tests/layouts/static/one-col/one-col.tpl.php
+++ /dev/null
@@ -1,18 +0,0 @@
-<?php
-/**
- * @file
- * Template for a one column layout.
- *
- * This template provides a very simple "one column" display layout.
- *
- * Variables:
- * - $content: An array of content, each item in the array is keyed to one
- *   region of the layout. This layout supports the following sections:
- *   $content['middle']: The only region in the layout.
- */
-?>
-<div class="layout-display layout-one-col clearfix">
-  <div class="layout-region layout-col">
-    <div class="inside"><?php print $content['middle']; ?></div>
-  </div>
-</div>
diff --git a/core/modules/layout/tests/themes/layout_test_theme/layouts/static/two-col/two-col.html.twig b/core/modules/layout/tests/themes/layout_test_theme/layouts/static/two-col/two-col.html.twig
new file mode 100644
index 0000000000000000000000000000000000000000..7c58a551b7c414ffec2974a891734cb03acbf5c0
--- /dev/null
+++ b/core/modules/layout/tests/themes/layout_test_theme/layouts/static/two-col/two-col.html.twig
@@ -0,0 +1,26 @@
+{#
+/**
+ * @file
+ * Template for a 2 column layout.
+ *
+ * This template provides a two column display layout, with each column equal in
+ * width.
+ *
+ * Available variables:
+ * - content: All content items, each content item is keyed to one region of the
+ *   layout. 'content' contains the following sections:
+ *   - left: Content in the left column.
+ *   - right: Content in the right column.
+ *
+ * @ingroup themeable
+ */
+#}
+<div class="layout-display layout-two-col clearfix">
+  <div class="layout-region layout-col-left">
+    <div class="inside">{{ content.left }}</div>
+  </div>
+
+  <div class="layout-region layout-col-right">
+    <div class="inside">{{ content.right }}</div>
+  </div>
+</div>
diff --git a/core/modules/layout/tests/themes/layout_test_theme/layouts/static/two-col/two-col.tpl.php b/core/modules/layout/tests/themes/layout_test_theme/layouts/static/two-col/two-col.tpl.php
deleted file mode 100644
index 1d8dbe46b33659eec0facccece2c833396954886..0000000000000000000000000000000000000000
--- a/core/modules/layout/tests/themes/layout_test_theme/layouts/static/two-col/two-col.tpl.php
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-/**
- * @file
- * Template for a 2 column layout.
- *
- * This template provides a two column display layout, with each column equal in
- * width.
- *
- * Variables:
- * - $content: An array of content, each item in the array is keyed to one
- *   region of the layout. This layout supports the following sections:
- *   - $content['left']: Content in the left column.
- *   - $content['right']: Content in the right column.
- */
-?>
-<div class="layout-display layout-two-col clearfix">
-  <div class="layout-region layout-col-left">
-    <div class="inside"><?php print $content['left']; ?></div>
-  </div>
-
-  <div class="layout-region layout-col-right">
-    <div class="inside"><?php print $content['right']; ?></div>
-  </div>
-</div>