A well-defined multiarm star copolymer, hyperbranched poly(glycidol)-b-poly(methyl methacrylate) (PGOH-b-PMMA), is used as a modifier in the curing of diglycidylether of bisphenol A (DGEBA) using 1-methyl imidazole (1MI) as anionic initiator. The effect of the polymer topology on the curing and gelation processes is studied. The addition of the PGOH-b-PMMA to the resin leaves the complex viscosity unaltered. The addition of the modifier decreases the shrinkage after gelation compared to that measured in the curing of the neat resin. By DMTA a single relaxation process in the pure DGEBA and modified thermoset is found. The addition of the star-like modifier led to an improvement on the mechanical characteristics such as the impact strength and microhardness in comparison to the neat material.