Abstract: A radiation-polymerizable composition contains at least one radiation curable acrylate resin oligomer prepared by reacting an alkoxylated polyol with a first acid component which includes an ethylenically unsaturated carboxylic acid; and a rheology modifier prepared by reacting a diepoxide with a second acid component which includes an ethylenically unsaturated carboxylic acid or reactive derivative thereof in the presence of a polyamide based on a polymerized fatty acid. The ethylenically unsaturated carboxylic acids of the first and second acid components are preferably acrylic acid or methacrylic acids. The diepoxide is preferably a diglycidyl ether such as bisphenol A. Colorants such as pigments or dyes optionally may be incorporated into the composition to form a printing ink which is curable by ultraviolet (UV) or electron beam radiation.