A radiation curable aqueous dispersion comprising a mixture of a first dispersion and a second dispersion, said first dispersion comprising at least one (meth)acrylated pre-polymer and, optionally, at least one ethylenically unsaturated compound, and said second dispersion comprising at least one thiol-functional compound, wherein the equivalent ratio between (i) the concentration of thiol groups and (ii) the concentration of meth(acrylate) groups and, if present of ethylenically unsaturated groups is 0.45 or less, wherein said concentrations are expressed in milli-equivalents per gram of solid contained in said aqueous dispersion; said radiation curable aqueous dispersion further comprising a photoinitiator, wherein said (meth)acrylated (poly)urethane pre-polymer is obtained from the reaction of: - at least one polyisocyanate compound (ia), - preferably, at least one polyol (iia), - at least one hydrophilic compound (iiia) containing at least one reactive group capable to react with isocyanate groups, said hydrophilic compound (iiia) being capable to render the (poly)urethane pre-polymer dispersible in aqueous medium either directly or after the reaction with a neutralizing agent to provide a salt, and - at least one (meth)acrylated compound (va) containing essentially one reactive group capable to react with isocyanate groups, wherein said second dispersion comprises at least one thiol-functional compound which is a thiol-functional (poly)urethane pre-polymer which carries groups which impart water dispersibility to the (poly)urethane and/or at least one thiol-functional pre-polymer which carries groups which impart water dispersibility to the pre-polymer, and which is prepared from monomers capable of free radical polymerization and having C=C double bonds by the method of free radical mass or solution polymerization, or wherein said second dispersion comprises an admixture of: (i) at least one polyurethane polymer which carries groups which impart water dispersibility to the polyurethane and/or at least one polymer which carries groups which impart water dispersibility to the polymer, prepared from monomers capable of free radical polymerization and having C=C double bonds by the method of free radical mass or solution polymerization, the polyurethane polymer and the polymer comprising less than 0.05 milli-equivalents of thiol groups per gram; and (ii) at least one thiol-functional compound comprising at least two thiol groups, said compound having a solubility of at most 1 g/l in water and a molecular weight of less than 10000. - at least one polyisocyanate compound (ia), - preferably, at least one polyol (iia), - at least one hydrophilic compound (iiia) containing at least one reactive group capable to react with isocyanate groups, said hydrophilic compound (iiia) being capable to render the (poly)urethane pre-polymer dispersible in aqueous medium either directly or after the reaction with a neutralizing agent to provide a salt, and - at least one (meth)acrylated compound (va) containing essentially one reactive group capable to react with isocyanate groups, (i) at least one polyurethane polymer which carries groups which impart water dispersibility to the polyurethane and/or at least one polymer which carries groups which impart water dispersibility to the polymer, prepared from monomers capable of free radical polymerization and having C=C double bonds by the method of free radical mass or solution polymerization, the polyurethane polymer and the polymer comprising less than 0.05 milli-equivalents of thiol groups per gram; and (ii) at least one thiol-functional compound comprising at least two thiol groups, said compound having a solubility of at most 1 g/l in water and a molecular weight of less than 10000.