A novel primer composition which does not need to be thermally cured at a high temperature after it is applied to a plastic substrate and a transparent laminate, for example, a plastic lens for spectacles, which comprises the above primer composition and has high impact resistance and high heat resistance even when a transparent anti-reflection coat is formed. This transparent laminate comprises a transparent plastic substrate and a coating film formed on at least one side of the plastic substrate by applying and curing a liquid primer composition which comprises (A) a self-emulsifiable emulsion of a linear polyurethane having a pendant carboxylic acid group and no crosslinked structure between polymer chains, (B) a sol of an inorganic oxide having a hydrophobic group on the surface, and (C) a compound having 5 to 9 carbon atoms and at least one hydroxyl group and at least one oxygen atom other than an oxygen atom constituting a hydroxyl group in the molecule.