An object is to provide a resin composition having a high permittivity and a low dissipation factor, and also a low coefficient of thermal expansion and a good appearance, and suitably used for producing an insulation layer of a printed wiring board, and a prepreg, a resin sheet, a laminate, a metal foil-clad laminate, and a printed wiring board obtainable by using the resin composition. The resin composition contains: (A) BaTi4O9; (B) a filler different from the BaTi4O9 (A); and (C) a thermosetting resin; wherein a median particle size of the BaTi4O9 (A) is 0.10 to 1.00 μm, and a volume ratio of the BaTi4O9 (A) to the filler (B), the BaTi4O9(A):the filler (B), ranges from 15:85 to 80:20.