A locking mechanism for securing sliding glass panel units including an elongate threaded fastener having a threaded forward end section and a rear end section. This fastener has a knob or handle for rotating the fastener about its central axis, this knob being mounted on the rear end section. A mounting plate is used to rotatably mount the fastener in a support frame so that the fastener extends through a hole in the plate and the support frame. An anchor with a threaded aperture is fixedly mounted in the sliding glass panel unit and this aperture is capable of threadedly receiving the forward end section of the fastener. Preferably a spring is arranged on the fastener between the mounting plate and the knob or handle, this spring acting to bias the fastener away from the anchor. The mechanism can be used with either sliding glass windows or sliding glass doors.