To provide a composition for forming films with low dielectric constant allowing formation of films excellent in mechanical strength, an insulating film obtained using the composition for forming films, and an electronic device having the insulating film.

The composition for forming the films contains a compound having at least one of a structure represented by the formula (A) and a structure represented by the formula (B) and/or a polymer polymerized using at least the compound. An insulating film obtained using the composition for forming films and an electronic device having the insulating film are also provided. In the formulae, each R1 independently represents hydrogen atom, alkyl, phenyl, phenoxy, naphthyl, adamantyl, diamantyl, or a structure represented by the formula (B), and each R2 independently represents hydrogen atom, alkyl, phenyl, phenoxy, or a polymerizable group, at least one R2 being a polymerizable group.