Telescopic rail includes first rail and second rail supported against each other to be linearly slidable in relation to each other in an extending direction from a first position into a second position, and locking device. The locking device includes stop element on first rail, mass element held on second rail and movable in relation to second rail in the extending direction or against the extending direction, spring element resiliently pretensioning mass element with a spring force, and locking element. The spring force has a force direction in the extending direction or against the extending direction. Mass element is movable against the spring force from an idle position into a triggering position, and, through a movement of mass element against the spring force, locking element is movable from an unlocked position into a locking position such that locking element in the locking position can be brought into engagement with stop element.