A high flow polyester composition is disclosed, which comprises at least one polyester, at least one flow enhancing ingredient of structure (III), ##STR00001## wherein R.sub.3 is a C1-C20 alkyl group optionally having one or more hydroxy group substituents, a C3-C20 cycloalkyl group, a C6-C20 aryl group, a C1-C20 alkoxy group optionally having one or more hydroxy group substituents, or a C6-C20 aryloxy group; and a dicycloaliphatic diepoxy compound, in an amount sufficient to provide 5 to 300 milliequivalents of epoxy per kilogram of polyester. The composition further optionally comprises reinforcing fillers, impact modifiers, a property-enhancing thermoplastic such as polycarbonate and flame retardant chemicals. The compositions are suitable for making automotive, electric and electronic parts.