diff --git a/lib/Unexpected.js b/lib/Unexpected.js
index c4870fe47..fa5a8b5d5 100644
--- a/lib/Unexpected.js
+++ b/lib/Unexpected.js
@@ -174,6 +174,10 @@ var customTypePrototype = {
 
 Unexpected.prototype.addType = function (type) {
     var baseType;
+    if (typeof type.name !== 'string' || trim(type.name) === '') {
+        throw new Error('A custom type must be given a non-empty name');
+    }
+
     if (type.base) {
         baseType = utils.findFirst(this.types, function (t) {
             return t.name === type.base;
diff --git a/test/unexpected.spec.js b/test/unexpected.spec.js
index 184767fa8..41330e1e8 100644
--- a/test/unexpected.spec.js
+++ b/test/unexpected.spec.js
@@ -1754,6 +1754,7 @@ describe('unexpected', function () {
         beforeEach(function () {
             clonedExpect = expect.clone();
             clonedExpect.addType({
+                name: 'box',
                 identify: function (obj) {
                     return obj && typeof obj === 'object' && obj.isBox;
                 },
@@ -1774,6 +1775,12 @@ describe('unexpected', function () {
             });
         });
 
+        it('throws an expection is the type has an empty or undefined name', function () {
+            expect(function () {
+                clonedExpect.addType({});
+            }, 'to throw', 'A custom type must be given a non-empty name');
+        });
+
         it('should use the equal defined by the type', function () {
             clonedExpect(box(123), 'to equal', box(123));
             clonedExpect(box(123), 'not to equal', box(321));