diff --git a/lib/template-loader.php b/lib/template-loader.php
index e68f1740c711b..82a86e7a539e3 100644
--- a/lib/template-loader.php
+++ b/lib/template-loader.php
@@ -148,7 +148,7 @@ function create_auto_draft_for_template_part_block( $block ) {
 				array(
 					'post_type'      => 'wp_template_part',
 					'post_status'    => array( 'publish', 'auto-draft' ),
-					'name'           => $block['attrs']['slug'],
+					'title'          => $block['attrs']['slug'],
 					'meta_key'       => 'theme',
 					'meta_value'     => $block['attrs']['theme'],
 					'posts_per_page' => 1,
diff --git a/packages/block-library/src/template-part/edit/use-template-part-post.js b/packages/block-library/src/template-part/edit/use-template-part-post.js
index 7ef0f705da2dc..73e027f27eb36 100644
--- a/packages/block-library/src/template-part/edit/use-template-part-post.js
+++ b/packages/block-library/src/template-part/edit/use-template-part-post.js
@@ -2,6 +2,7 @@
  * WordPress dependencies
  */
 import { useSelect } from '@wordpress/data';
+import { cleanForSlug } from '@wordpress/url';
 
 export default function useTemplatePartPost( postId, slug, theme ) {
 	return useSelect(
@@ -22,18 +23,19 @@ export default function useTemplatePartPost( postId, slug, theme ) {
 			// load the auto-draft created from the
 			// relevant file.
 			if ( slug && theme ) {
+				const cleanedSlug = cleanForSlug( slug );
 				const posts = select( 'core' ).getEntityRecords(
 					'postType',
 					'wp_template_part',
 					{
 						status: [ 'publish', 'auto-draft' ],
-						slug,
+						slug: cleanedSlug,
 						theme,
 					}
 				);
 				const foundPosts = posts?.filter(
 					( post ) =>
-						post.slug === slug &&
+						post.slug === cleanedSlug &&
 						post.meta &&
 						post.meta.theme === theme
 				);