A vehicle seatbelt assembly includes a first member, a second member, a buckle mechanism, and a clutch mechanism. The first member is configured to attach to one of a vehicle floor structure and a seat structure. The second member is supported on the first member. The second member is configured for limited sliding movement relative to the first member. The buckle mechanism is attached to the second member for movement therewith. The buckle mechanism has a latch device configured to releaseably retain a seatbelt latch tongue member. The clutch mechanism is disposed between the first member and the second member and is operable to switch between a dis-engaged state and an engaged state. In the dis-engaged state, the clutch mechanism allows movement of the second member relative to the first member. In the engaged state, the clutch mechanism prevents movement of the second member relative to the first member.