The present invention provides a resin composition containing a reactive monomer and/or oligomer having allyl ester groups, a film of the resin composition which is excellent in transparency and heat resistance and has a high thickness precision, and a process for producing such a film. The resin composition includes (A) a reactive oligomer having allyl ester groups and represented by the general formula (1): wherein R1 represents an alkanediyl or alkenediyl group having 1 to 4 carbon atoms with the proviso that a plurality of R1 groups may be the same or different, R2 represents a cycloalkanediyl, cycloalkenediyl or arenediyl group with the proviso that a plurality of R2 groups may be the same or different, and n represents an average degree of polymerization and is a number of 1 to 30; (B) a polyfunctional (meth)acrylic monomer and/or oligomer; and (C) a thermal polymerization initiator.