diff --git a/lib/test.js b/lib/test.js
index e6fad242..398a68e6 100644
--- a/lib/test.js
+++ b/lib/test.js
@@ -4,6 +4,7 @@ var path = require('path');
 var inherits = require('inherits');
 var EventEmitter = require('events').EventEmitter;
 var has = require('has');
+var isRegExp = require('is-regex');
 var trim = require('string.prototype.trim');
 var bind = require('function-bind');
 var forEach = require('for-each');
@@ -502,7 +503,7 @@ Test.prototype['throws'] = function (fn, expected, msg, extra) {
 
     var passed = caught;
 
-    if (expected instanceof RegExp) {
+    if (isRegExp(expected)) {
         passed = expected.test(caught && caught.error);
         expected = String(expected);
     }
diff --git a/package.json b/package.json
index 9036c0f3..b3ad3dd9 100644
--- a/package.json
+++ b/package.json
@@ -16,6 +16,7 @@
         "glob": "~7.1.4",
         "has": "~1.0.3",
         "inherits": "~2.0.4",
+        "is-regex": "~1.0.4",
         "minimist": "~1.2.0",
         "object-inspect": "~1.6.0",
         "resolve": "~1.11.1",