An objective of the present invention is to provide an organic-inorganic hybrid acrylic polymer having an increased refractive index, which has a higher transparency and a less impaired scratch resistance; a metal oxide dispersion and a polymerizable composition as materials for the polymer; and the organic-inorganic hybrid polymer capable of being produced in a crack-free manner. Another objective of the present invention is to provide a high-performance antireflection film using the organic-inorganic hybrid polymer. The metal oxide dispersion of the present invention comprises a phosphorus compound represented by Formula (1): (wherein, R1 is a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an aryl group, an aliphatic heterocyclic group, or an aromatic heterocyclic group; R2 is an organic residue; and n is 1 or 2) and a metal oxide.