A resin composition comprising a prepolymer and a thermosetting component, the prepolymer being obtained by polymerizing an alkenyl-substituted nadimide, a maleimide compound, and an amino-modified silicone, wherein the alkenyl-substituted nadimide comprises a compound represented by following general formula: wherein each R 1 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R 2 represents an alkylene group having 1 to 6 carbon atoms, a phenylene group, a biphenylene group, a naphthylene group, or a group represented by following general formula or: wherein R 3 represents a methylene group, an isopropylidene group, or a substituent represented by CO, O, S, or SO 2, and wherein each R 4 independently represents an alkylene group having 1 to 4 carbon atoms, or a cycloalkylene group having 5 to 8 carbon atoms, and wherein the amino-modified silicone comprises a compound represented by following general formula: wherein each Rg independently represents a hydrogen atom, a methyl group, or a phenyl group, each R 10 independently represents an alkylene group having 1 to 10 carbon atoms and optionally having a side chain, and n represents an integer of 0 or larger, wherein the content of the prepolymer is 10 to 90% by mass and the content of the thermosetting component is 10 to 90% by mass of the resin composition, wherein the content of the alkenyl-substituted nadimide is 10 to 60 parts by mass based on 100 parts by mass in total of the prepolymer and the thermosetting component, wherein the content of the maleimide compound is 30 to 80 parts by mass based on 100 parts by mass in total of the prepolymer and the thermosetting component, and wherein the content of the amino-modified silicone is 1 to 40 parts by mass based on 100 parts by mass in total of the prepolymer and the thermosetting component. wherein the alkenyl-substituted nadimide comprises a compound represented by following general formula: wherein each R 1 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R 2 represents an alkylene group having 1 to 6 carbon atoms, a phenylene group, a biphenylene group, a naphthylene group, or a group represented by following general formula or: wherein R 3 represents a methylene group, an isopropylidene group, or a substituent represented by CO, O, S, or SO 2, and wherein each R 4 independently represents an alkylene group having 1 to 4 carbon atoms, or a cycloalkylene group having 5 to 8 carbon atoms, and wherein each R 1 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R 2 represents an alkylene group having 1 to 6 carbon atoms, a phenylene group, a biphenylene group, a naphthylene group, or a group represented by following general formula or: wherein R 3 represents a methylene group, an isopropylidene group, or a substituent represented by CO, O, S, or SO 2, and wherein each R 4 independently represents an alkylene group having 1 to 4 carbon atoms, or a cycloalkylene group having 5 to 8 carbon atoms, and wherein the amino-modified silicone comprises a compound represented by following general formula: wherein each Rg independently represents a hydrogen atom, a methyl group, or a phenyl group, each R 10 independently represents an alkylene group having 1 to 10 carbon atoms and optionally having a side chain, and n represents an integer of 0 or larger, wherein the content of the prepolymer is 10 to 90% by mass and the content of the thermosetting component is 10 to 90% by mass of the resin composition, wherein the content of the alkenyl-substituted nadimide is 10 to 60 parts by mass based on 100 parts by mass in total of the prepolymer and the thermosetting component, wherein the content of the maleimide compound is 30 to 80 parts by mass based on 100 parts by mass in total of the prepolymer and the thermosetting component, and wherein the content of the amino-modified silicone is 1 to 40 parts by mass based on 100 parts by mass in total of the prepolymer and the thermosetting component.