Melt blending of poly(lactic acid) (PLA) and ethylene/methyl acrylate/glycidyl methacrylate terpolymer (EGA) containing relatively high-concentration epoxide groups (8 wt%) was performed to improve the toughness and crystallization of PLA. The results of nonisothermal and isothermal crystallization investigation showed that the addition of EGA accelerated the crystallization rate and increased the final crystallinity of PLA in the blends. Significant enhancement in toughness and flexibility of PLA were achieved by the incorporation of the EGA elastomer. When 20 wt% EGA added, the impact strength increased from 3.0 kJ m−2 of neat PLA to 59.8 kJ m−2 and the elongation at break increased from 4.9 to 232.0%. The failure mode changed from brittle fracture of neat PLA to ductile fracture of the blend. POLYM. ENG. SCI., 53:2498–2508, 2013. © 2013 Society of Plastics Engineers