An aqueous dispersion of polymer particles wherein the polymer comprises both (a) polar groups selected from amine, ureido and thioureido groups, and (b) poly (alkylene oxide) chains covalently bonded to the polymer, the polymer comprising at least 0.1% by weight of (a), at least 0.2% of (b) and from 0.4-9.0% of (a)+(b). Dispersions according to the invention are useful in latex paint compositions, and these compositions exhibit very good moisture resistance properties.