Abstract: The subject of the present invention is the use, in, and for the preparation of, cosmetic or dermatological compositions, of a copolymer which can be obtained by copolymerization of a monomer mixture comprising:(a) from 5 to 25% by weight of at least one monomer (A) with ethylenic unsaturation containing at least one carboxylic acid function;(b) from 3 to 30% by weight of at least one monomer (B) of formula (I):H.sub.2 C=C(R.sub.1)--COOR.sub.2 (I)in whichR.sub.1 denotes a hydrogen atom or a methyl radical,R.sub.2 denotes a saturated or unsaturated, linear or branched or cyclic alkyl radical or an aromatic radical, having from 8 to 40 carbon atoms,(c) at least one monomer (C) chosen from the group consisting of tert-butyl methacrylate, tert-butyl acrylate and mixtures thereof, in a proportion greater than 50%, such that the glass transition (Tg) of the polymer is greater than or equal to 15.degree. C.