Thermosetting powder coating compositions comprising a curable particulate resinous material and a flow control agent which is a copolymer of an alkyl acrylate or methacrylate containing from 6 to 20 carbon atoms in the alkyl group and a hydroxyalkyl acrylate or methacrylate. The flow modifiers enhance the rheology of the thermosetting powder coating composition providing for smoother coatings while at the same time not adversely affecting appearance or adhesion with associated coatings, for example, previously applied electrodeposited primers or subsequently applied topcoats.