diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-themes-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-themes-controller.php
index a1203f236423f..8e7e6ae8e0c5d 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-themes-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-themes-controller.php
@@ -332,6 +332,10 @@ public function prepare_item_for_response( $item, $request ) {
 			$data['is_block_theme'] = $theme->is_block_theme();
 		}
 
+		if ( rest_is_field_included( 'has_theme_json', $fields ) ) {
+			$data['has_theme_json'] = wp_theme_has_theme_json();
+		}
+
 		if ( rest_is_field_included( 'stylesheet_uri', $fields ) ) {
 			if ( $this->is_same_theme( $theme, $current_theme ) ) {
 				$data['stylesheet_uri'] = get_stylesheet_directory_uri();
@@ -546,6 +550,11 @@ public function get_item_schema() {
 					'type'        => 'boolean',
 					'readonly'    => true,
 				),
+				'has_theme_json'              => array(
+					'description' => __( 'Whether the theme has a theme.json file.' ),
+					'type'        => 'boolean',
+					'readonly'    => true,
+				),
 				'name'                        => array(
 					'description' => __( 'The name of the theme.' ),
 					'type'        => 'object',
diff --git a/tests/phpunit/tests/rest-api/rest-themes-controller.php b/tests/phpunit/tests/rest-api/rest-themes-controller.php
index 923e7cda27374..fa5dc4e462e6d 100644
--- a/tests/phpunit/tests/rest-api/rest-themes-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-themes-controller.php
@@ -180,6 +180,7 @@ public function test_get_items() {
 			'default_template_types',
 			'description',
 			'is_block_theme',
+			'has_theme_json',
 			'name',
 			'requires_php',
 			'requires_wp',
@@ -222,6 +223,7 @@ public function test_get_items_inactive() {
 			'author_uri',
 			'description',
 			'is_block_theme',
+			'has_theme_json',
 			'name',
 			'requires_php',
 			'requires_wp',
@@ -363,7 +365,7 @@ public function test_get_item_schema() {
 		$response   = self::perform_active_theme_request( 'OPTIONS' );
 		$data       = $response->get_data();
 		$properties = $data['schema']['properties'];
-		$this->assertCount( 20, $properties );
+		$this->assertCount( 21, $properties );
 
 		$this->assertArrayHasKey( 'author', $properties );
 		$this->assertArrayHasKey( 'raw', $properties['author']['properties'] );
@@ -381,6 +383,7 @@ public function test_get_item_schema() {
 		$this->assertArrayHasKey( 'default_template_types', $properties );
 
 		$this->assertArrayHasKey( 'is_block_theme', $properties );
+		$this->assertArrayHasKey( 'has_theme_json', $properties );
 
 		$this->assertArrayHasKey( 'name', $properties );
 		$this->assertArrayHasKey( 'raw', $properties['name']['properties'] );
@@ -546,6 +549,27 @@ public function test_theme_is_block_theme() {
 		$this->assertTrue( $result[0]['is_block_theme'] );
 	}
 
+	/**
+	 * @ticket 63253
+	 * @covers WP_REST_Themes_Controller::prepare_item_for_response
+	 */
+	public function test_theme_has_theme_json() {
+		// Test classic theme (Theme without theme.json).
+		$response = self::perform_active_theme_request();
+		$result   = $response->get_data();
+
+		$this->assertArrayHasKey( 'has_theme_json', $result[0] );
+		$this->assertFalse( $result[0]['has_theme_json'] );
+
+		// Test block theme (Theme with theme.json).
+		switch_theme( 'block-theme' );
+		$response = self::perform_active_theme_request();
+		$result   = $response->get_data();
+
+		$this->assertArrayHasKey( 'has_theme_json', $result[0] );
+		$this->assertTrue( $result[0]['has_theme_json'] );
+	}
+
 	/**
 	 * @ticket 49906
 	 */
@@ -1372,6 +1396,7 @@ public function test_get_item() {
 			'author_uri',
 			'description',
 			'is_block_theme',
+			'has_theme_json',
 			'name',
 			'requires_php',
 			'requires_wp',