diff --git a/src/wp-includes/rest-api.php b/src/wp-includes/rest-api.php
index 7480fd5c64..675c545ce1 100644
--- a/src/wp-includes/rest-api.php
+++ b/src/wp-includes/rest-api.php
@@ -2818,6 +2818,11 @@ function rest_preload_api_request( $memo, $path ) {
 		}
 	}
 
+	$path = untrailingslashit( $path );
+	if ( empty( $path ) ) {
+		$path = '/';
+	}
+
 	$path_parts = parse_url( $path );
 	if ( false === $path_parts ) {
 		return $memo;
diff --git a/tests/phpunit/tests/rest-api.php b/tests/phpunit/tests/rest-api.php
index 288c7140e8..4ec818013b 100644
--- a/tests/phpunit/tests/rest-api.php
+++ b/tests/phpunit/tests/rest-api.php
@@ -954,6 +954,31 @@ class Tests_REST_API extends WP_UnitTestCase {
 		$GLOBALS['wp_rest_server'] = $rest_server;
 	}
 
+	/**
+	 * @ticket 51636
+	 */
+	function test_rest_preload_api_request_removes_trailing_slashes() {
+		$rest_server               = $GLOBALS['wp_rest_server'];
+		$GLOBALS['wp_rest_server'] = null;
+
+		$preload_paths = array(
+			'/wp/v2/types//',
+			array( '/wp/v2/media///', 'OPTIONS' ),
+			'////',
+		);
+
+		$preload_data = array_reduce(
+			$preload_paths,
+			'rest_preload_api_request',
+			array()
+		);
+
+		$this->assertSame( array_keys( $preload_data ), array( '/wp/v2/types', 'OPTIONS', '/' ) );
+		$this->assertArrayHasKey( '/wp/v2/media', $preload_data['OPTIONS'] );
+
+		$GLOBALS['wp_rest_server'] = $rest_server;
+	}
+
 	/**
 	 * @ticket 40614
 	 */