A headrest has a base carrying the headrest on a seat, a head piece forming an abutment for a head, and a four-bar linkage including a first link and at least one second link therebehind in a direction of displacement. Each link is secured at one pivot with the base and at another pivot with the head piece such that the head piece is movable by the four-bar linkage relative to the base between a first end position and a second end position. An adjuster can alter and/or arrest the relative position between one of the links and the head piece, or between one of the links and the base. This adjuster has a first slotted link fixed on one of the first and second links, a second slotted link fixed on the head piece or the base, and a slide block engaged in slots of the first and second slotted links.