Abstract: A prepreg having low water absorption, and having remarkably suppressed deterioration in insulation resistance over time, and further having excellent heat resistance, a metal foil-clad laminate using the prepreg, and a printed wiring board using the metal foil-clad laminate are provided. A prepreg of the present invention is obtained by impregnating or coating a base material (D) with a resin composition comprising: a naphthol-modified dimethylnaphthalene formaldehyde resin (A); an epoxy resin (B) having an epoxy equivalent of 200 to 400 g/eq.; and an inorganic filler (C).