A resin composition for powder coating, comprising(A) a carboxyl group-containing resin having a number average molecular weight of 1000 to 20000, an acid value of 5 to 200 and a glass transition temperature of 30 to 120.degree. C.,(B) bis(.beta.-methylglycidyl)terephthalate of the formula (1): ##STR1## as a curing agent, and (D) at least one compound selected from the group consisting of amines having the linkage of the formula (2): ##STR2## in the molecule, a triarylphosphines and onium salts as a ring-opening polymerization inhibitor, the equivalent ratio of (.beta.-methylglycidyl group of the component (B))/(carboxyl group of the component (A)) being 0.5 to 3.0. The composition can give a product of curing excellent in impact resistance, weathering resistance and so on.