A solid electrolyte composition according to the present disclosure includes a halide solid electrolyte material and an organic solvent. The halide solid electrolyte material has an average particle size of less than or equal to 1 μm. The organic solvent consists of at least one selected from the group consisting of a compound having a functional group and a hydrocarbon. The functional group includes at least one selected from the group consisting of an ether group and a halogen group.