Abstract: A coating composition comprises a hydroxy component having at least two free hydroxyl groups per molecule and an anhydride component which is a polymer-containing cyclic carboxylic acid anhydride groups derived from an olefinically unsaturated cyclic carboxylic acid anhydride, the two components being packaged separately during storage of the composition and being compatible on mixing. At least one of the components is a film-forming polymer. The composition includes a catalytically effective amount of amine groups for accelerating the curing reaction between the hydroxyl groups and the anhydride groups. The amine groups are present in the molecule of the hydroxy component or in a separate amine compound. The hydroxy component is preferably a film-forming acrylic copolymer having pendent hydroxyl and dialkyl-amino-alkyl groups. The composition is particularly useful as a glossy pigmented coating for rigid substrates such as vehicle bodies where hardening of the coating at ambient temperature is required.