<p>I have a model and two views set up like this:</p>

<pre><code>Model ---&gt; OSortFilterProxyModel ---&gt; OListView
Model ------------------------------&gt; OTableView
</code></pre>

<p>When the user selects something in one of the views, I want the other view to mirror that selection. So I thought I'd use a QSelectionModel to link them together. But this does not work. I have a feeling it is because the views think they have two different models, when in fact they have the same model. Is there a way to get this to work?</p>

What is probably happening is that the views do have two different models.  One is your original model, the other is the sort filter model.
I'm not sure if this would work, and it depends on what Qt considers "activated", but you could connect a function to each of the view's activated slots.  These will pass you a model index.  You'll have to send the model index through the proxy model in the appropriate direction (mapFromSource and mapToSource).  Then, call the setCurrentIndex on the other view.
The documentation for the activated signal states that what is considered "activated" varies by platform.  There might be other signals you could latch onto, such as the selection model's selection changed signal.  You might have to do a different call to change the selection as seen by the user.  And finally, it might be possible or even easier to do in a derived QSelectionModel, as long as you remember about mapping to/from the source model.