An attractive window lock for conventional double hung windows is provided with a housing containing a handle and a cam. The housing defines a pair of grooves which are complementary shaped to the ends of a mounting plate. The mounting plate is affixed with fasteners to the window sash and the housing is then slideably joined to the mounting plate, concealing the mounting plate and fasteners and providing an attractive appearance for the owner. A keeper is affixed to the opposing sash and by rotating the handle on the housing the rotatable cam extends and engages the keeper to secure the sashes in place.