Disclosed are a method of manufacturing a solid electrolyte, a solid electrolyte manufactured using the method, and an all-solid cell including the solid electrolyte. The method includes preparing an electrolyte admixture including a solid electrolyte precursor and a solvent, drying the electrolyte admixture and removing the solvent from the electrolyte admixture to form a dry electrolyte mixture, and heat-treating the dry electrolyte mixture to form a crystallized solid electrolyte.