Abstract: A window security means for double hung casement windows includes a lower tube, open at its upper end and having a metal box rigidly fastened to its lower end, with the box being open at its bottom and shaped to fit over the window lock on one movable part of the window. An upper tube is telescoped within the lower tube and adapted at its upper end to engage another movable part of the window. A fastener is provided to fasten the upper tube immovably within the lower tube, and a shield can surround the fastener and limit access to the fastener to access essentially from one direction.