Summary Dodecyloxy poly(ethylene glycol) methacrylates with a degree of polymerization from 9 to 20 were used as comonomers in the dispersion polymerization of benzyl methacrylate (BzRA) and styrene (St) to obtain soapless emulsions stabilized by the resulting graft copolymers. In the aqueous dispersion with BzMA, the apparent reactivities of the macromonomers were essentially the same as those observed in the benzene solution, while in heptane they increased as also found in the case of the aqueous dispersion with St. The latter fact suggests a preferential polymerization near on the surface of the micellar particles where the macromonomers are enriched.