 <p>In the past, when we had to do something like this, we just used apply (<a href="http://jsfiddle.net/85TeD/1/" rel="nofollow">http://jsfiddle.net/85TeD/1/</a>):</p> <pre><code>function UsersListViewModel() { var self = this; ListViewModel.apply(self); self.OtherProp = ko.observable("other"); } </code></pre> <p>If you want to implement full classical inheritance, this is a start: <a href="http://www.crockford.com/javascript/inheritance.html" rel="nofollow">http://www.crockford.com/javascript/inheritance.html</a> </p>