Free radical copolymerization of glycidyl methacrylate (GMA) and styrene (ST) is systematically investigated using low conversion pulsed laser polymerization (PLP) experiments. It is shown that GMA, like other methacrylate monomers, undergoes significant depropagation at elevated temperatures. While ST/GMA copolymer composition is well represented by the terminal model, the copolymer-averaged propagation rate coefficient for the system is not; the latter quantity is represented using the implicit penultimate unit model. The PLP data are used to estimate GMA depropagation kinetics as well as ST/GMA monomer (r(ST) = 0.31 and r(GMA) = 0.51) and radical (s(ST), = 0.28 and S-GMA = 1,05) reactivity ratios, which show no significant variation in the 50-140 degrees C temperature range examined. The GMA/ST copolymerization behavior is compared to that of butyl methacrylate (BMA) with ST; GMA monomer is more active toward styrene radicals than BMA, and a GMA unit in the penultimate position of styrene radicals reduces copolymerization propagation to a greater extent.