 <p>I've seen this happen because of an <code>img</code> tag with a blank <code>src</code> attribute. Giving an <code>img</code>, <code>script</code>, <code>link</code> or similar tag a <code>src</code> or <code>href</code> attribute <code>=""</code> will resolve to the current page. So it will try to load the page a second time as it tried to load the asset. It could also be in a CSS <code>url()</code> property or an AJAX call.</p> <p>One easy way to tell is to temporarily put something like <code>&lt;base href="http://example.com" /&gt;</code> in your <code>&lt;head&gt;</code> section. That will prefix any links on the page, which should prevent your local page from being called twice if it is that sort of problem.</p> <p>I've also seen some browser extensions that query the page in a separate request. I've noticed this specifically with the <a href="https://chrome.google.com/webstore/detail/najdkmbedaehkepolllmpdfccdgooajh">Web Server Notifier</a> and <a href="https://chrome.google.com/webstore/detail/fnpgnmindcbkjbpblcklealdhnogmlko">Web Technology Notifier</a> extensions for Chrome. Try an "incognito" window or a separate browser and see if you get the same result.</p>