The anionic copolymerization of a Diglycidyl ether of bisphenol A (DGEBA) epoxy resin and a bislactone has been studied with different initiators. The kinetics of the process has been dealt with in detail, and it has been detected the existence of different competing curing mechanisms: a quasi-alternating copolymerization between the epoxy monomer and the bislactone, and homopolymerization of the epoxy resin. In presence of an excess of DGEBA, the copolymerization first takes place, and then the excess of epoxy monomer can homopolymerize. The bislactone induces an apparent accelerating effect because it reduces the extent of epoxy homopolymerization and therefore the termination reactions associated with it, thus allowing a complete cure with a reduced amount of initiator.