diff --git a/lib/template-loader.php b/lib/template-loader.php
index 82a86e7a539e3..9b8cea2a7fd6f 100644
--- a/lib/template-loader.php
+++ b/lib/template-loader.php
@@ -176,7 +176,9 @@ function create_auto_draft_for_template_part_block( $block ) {
 				}
 
 				if ( $template_part_file_path ) {
-					$file_contents = file_get_contents( $template_part_file_path );
+					ob_start();
+					include $template_part_file_path;
+					$file_contents = ob_get_clean();
 					if ( $template_part_post && $template_part_post->post_content === $file_contents ) {
 						$template_part_id = $template_part_post->ID;
 					} else {
@@ -214,7 +216,7 @@ function create_auto_draft_for_template_part_block( $block ) {
  * @param string[] $template_hierarchy (optional) The current template hierarchy, ordered by priority.
  * @return null|array {
  *  @type WP_Post|null template_post A template post object, or null if none could be found.
- *  @type int[] A list of template parts IDs for the template.
+ *  @type int[] template_part_ids A list of template parts IDs for the template.
  * }
  */
 function gutenberg_find_template_post_and_parts( $template_type, $template_hierarchy = array() ) {
@@ -283,8 +285,10 @@ function gutenberg_find_template_post_and_parts( $template_type, $template_hiera
 
 	// If there is, use it instead.
 	if ( isset( $higher_priority_block_template_path ) ) {
-		$post_name             = basename( $higher_priority_block_template_path, '.html' );
-		$file_contents         = file_get_contents( $higher_priority_block_template_path );
+		$post_name = basename( $higher_priority_block_template_path, '.html' );
+		ob_start();
+		include $higher_priority_block_template_path;
+		$file_contents         = ob_get_clean();
 		$current_template_post = array(
 			'post_content' => $file_contents,
 			'post_title'   => $post_name,
diff --git a/lib/template-parts.php b/lib/template-parts.php
index b09bd83ba0b86..21f7c9438a1bb 100644
--- a/lib/template-parts.php
+++ b/lib/template-parts.php
@@ -236,7 +236,9 @@ function get_template_part_paths( $base_directory ) {
 			}
 			// Build and save each template part.
 			foreach ( $template_part_files as $template_part_file ) {
-				$content = file_get_contents( $template_part_file );
+				ob_start();
+				include $template_part_file;
+				$content = ob_get_clean();
 				// Infer slug from filepath.
 				$slug = substr(
 					$template_part_file,
diff --git a/packages/block-library/src/template-part/index.php b/packages/block-library/src/template-part/index.php
index 29e3668170f2f..91c3027901717 100644
--- a/packages/block-library/src/template-part/index.php
+++ b/packages/block-library/src/template-part/index.php
@@ -41,7 +41,9 @@ function render_block_core_template_part( $attributes ) {
 			// render the corresponding file content.
 			$template_part_file_path = get_stylesheet_directory() . '/block-template-parts/' . $attributes['slug'] . '.html';
 			if ( 0 === validate_file( $template_part_file_path ) && file_exists( $template_part_file_path ) ) {
-				$content = file_get_contents( $template_part_file_path );
+				ob_start();
+				include $template_part_file_path;
+				$content = ob_get_clean();
 			}
 		}
 	}