To provide a water-based polymer dispersion for isocyanate-crosslinked adhesives comprising a polymer (1) which is obtained by emulsion polymerization of a monomer composition comprising at least one monomer selected from the group consisting of an aromatic vinyl monomer and a (meth)acrylate monomer, a crosslinkable monomer, and a different monomer, in respective predetermined amounts; and a polymer (2) which is obtained by emulsion polymerization of a monomer composition comprising at least one monomer selected from the group consisting of an aromatic vinyl monomer and a (meth)acrylate monomer, a hydroxyl group-containing vinyl monomer, an ethylenically unsaturated carboxylic acid monomer, and a different monomer, in respective predetermined amounts, wherein the polymers (1) and (2) have a Tg difference of 20 to 80.degree. C.