Disclosed are compositions comprised of (a)a polymer containing pendant and/or functional groups selected from the group consisting of carbamate, urethane and/or amide functional groups; and (b) a rheology modifier comprising the reaction product of an amine and an isocyanate; and, optionally, a polymer which is different from the polymer (a) which contains carbamate, urethane and/or amide functional groups. Also disclosed are curable compositions comprised of the compositions described above which further comprise (c) a curing agent having functional groups reactive with the functional groups of the polymer (a). The curable compositions are useful for a variety of applications such as adhesives, sealants and surface coatings where the presence of a carbamate, urethane and/or amide functional polymer in conjunction with the rheology modifier provides improved thixotropy and superior sag resistance.