Abstract: A positive action window lock for automatically locking a window in a closed position. The window includes a first segment and a second segment. The window lock includes a base mounted to the first segment, a slider movably mounted to the base and an engagement portion mounted to the second segment. The slider is moveable to and between release and locking positions. The slider is in engagement with the engagement portion when the first and second segments are in the closed position to generally prevent movement of the first segment relative to the second segment or to lock the window in the closed position.