A window wedge is used as a stop for a sliding type window such as a double hung window. The wedge has a strip of hook and loop material (VELCRO)(. TM. ) on its base. A second strip of mating hook and loop material can be affixed to the stile of one window. The wedge can than be attached to the stile at any point along the second strip of hook and loop material such that the other window can only open to the point where it is stopped by the wedge. The wedge can be quickly and easily moved to a different point along the strip on the stile, changing the amount the window can be opened.