Abstract: A time lock usable with a lock mechanism having a bolt displaceable along a path for opening a door has a housing which is fixed adjacent the path and in which a keeper is vertically displaceable between an uppermost blocking position, a lowermost unblocking position, and an intermediate position. A clockwork in the housing displaces a lock slide horizontally from a holding position wherein a recess in this lock slide is out of alignment with a dog pivoted in the housing into a freeing position with the recess and dog aligned after elapse of a predetermined interval of time. This locking dog is carried on a locking pawl which is connected via a shortenable link to the vertically displaceable keeper. When the clockwork displaces the lock slide into the freeing position the keeper automatically drops into the intermediate position, with the dog entering upwardly into the recess in the lock slide.