Powder coating compositions for low temperature cure between 100° C. and 150° C. The powder coating compositions contain: a) a carboxylic acid functional resin A which is a polyester resin A having carboxylic acid groups, b) a first glycidyl functional resin B1 which is a bisphenol A based epoxy resin having glycidyl groups, c) a second glycidyl functional resin B2 which is a phenol or cresol epoxy novolac resin having glycidyl groups, and d) at least one thermosetting curing catalyst C. Such powder coating compositions may exhibit, upon curing, an excellent combination of physical properties such as smoothness, flexibility, hardness and, above all, an outstanding durability for the MEK impregnation test.