A vehicle seat having a backrest and a seat part, as well as at least one sidewall arranged on the backrest or on the seat part, the sidewall having two support portions that are coupled together, by a coupling means, and are movable relative to one another, between which support portions at least one hollow body that can be filled with fluid is arranged, the relative position of the two support portions with respect to one another, and thus the outside contour of the sidewall, being variable by filling or emptying the at least one hollow body. The coupling means is designed such that, upon filling or emptying of the at least one hollow body, the two support portions are variable relative to one another, both in translation and in their angular position.