A locking device for vehicle seats, in particular motor vehicle seats, includes two mutually displaceable parts. A rail, associated to one of the parts, extends in the direction of displacement and has at least one row of snap-in holes extending longitudinally along the rail. These holes are separated from each other by web-like material sections. Ratchets, associated to the other part, can move in relation to the rail between a disengaging position and a locking position. They move perpendicularly to the direction of extension of the rail, and are controlled via an operating mechanism. When the mutually displaceable parts are in locked position, at least one of the ratchets engages in a corresponding snap-in hole. At least one retaining element prevents involuntary disengaging of the ratchet from an effective locking position. As a result, reliable locking is achieved, in particular in the event of a crash, which entails high frequency vibrational fractions.