An example of an ultraviolet (UV) curable inkjet ink composition includes a pigment dispersed by an anionic polymeric dispersant, an organic co-solvent, polyvinylpyrrolidone, a photoinitiator, a UV radiation curable polyurethane, and a balance of water. The polyvinylpyrrolidone has a number average molecular weight ranging from about 10,000 to about 40,000.