A polymerizable composition suitable for use in producing molded articles that can maintain a high refractive index, and can be prevented from cracking, peeling from a support, and dimensional changes due to a high-temperature thermal history. A polymerizable composition including (a) 100 parts by mass of a specific reactive silsesquioxane compound, (b) 10 to 500 parts by mass of a specific fluorene compound, and (c) 0.1 to 50 parts by mass of a polymer having a weight average molecular weight of 5,000 to 100,000; a cured product obtained by polymerizing the polymerizable composition; and a high-refractive-index resin lens material including the polymerizable composition.