diff --git a/src/event.js b/src/event.js
index a880bb647..0a85bf43c 100644
--- a/src/event.js
+++ b/src/event.js
@@ -403,7 +403,9 @@ jQuery.event = {
 					matches = [];
 					for ( i = 0; i < delegateCount; i++ ) {
 						handleObj = handlers[ i ];
-						sel = handleObj.selector;
+
+						// Don't conflict with Object.prototype properties (#13203)
+						sel = handleObj.selector + " ";
 
 						if ( matches[ sel ] === undefined ) {
 							matches[ sel ] = handleObj.needsContext ?
diff --git a/test/unit/event.js b/test/unit/event.js
index 041920a53..bc98f73cb 100644
--- a/test/unit/event.js
+++ b/test/unit/event.js
@@ -1797,6 +1797,20 @@ test( "delegated event with delegateTarget-relative selector", function() {
 	markup.remove();
 });
 
+test( "delegated event with selector matching Object.prototype property (#13203)", function() {
+	expect(1);
+
+	var matched = 0;
+
+	jQuery("#foo").on( "click", "toString", function( e ) {
+		matched++;
+	});
+
+	jQuery("#anchor2").trigger("click");
+
+	equal( matched, 0, "Nothing matched 'toString'" );
+});
+
 test("stopPropagation() stops directly-bound events on delegated target", function() {
 	expect(1);