diff --git a/src/wp-includes/collaboration.php b/src/wp-includes/collaboration.php
index 6fdbe2889ba7a..31f816c87b670 100644
--- a/src/wp-includes/collaboration.php
+++ b/src/wp-includes/collaboration.php
@@ -12,13 +12,25 @@
  * @since 7.0.0
  *
  * @access private
+ *
+ * @global string $pagenow The filename of the current screen.
  */
 function wp_collaboration_inject_setting() {
-	if ( get_option( 'wp_enable_real_time_collaboration' ) ) {
-		wp_add_inline_script(
-			'wp-core-data',
-			'window._wpCollaborationEnabled = true;',
-			'after'
-		);
+	global $pagenow;
+
+	if ( ! get_option( 'wp_enable_real_time_collaboration' ) ) {
+		return;
 	}
+
+	// Disable real-time collaboration on the site editor.
+	$enabled = true;
+	if ( 'site-editor.php' === $pagenow ) {
+		$enabled = false;
+	}
+
+	wp_add_inline_script(
+		'wp-core-data',
+		'window._wpCollaborationEnabled = ' . wp_json_encode( $enabled ) . ';',
+		'after'
+	);
 }