In one aspect the present disclosure relates to an aqueous inkjet ink composition comprising a yellow azo pigment, a pigment synergist, a polymeric dispersant, 5 to 20 wt % of a latex polymer, 5 to 40 wt % of an organic co-solvent that has a boiling point of a boiling point in the range of about 170° C. to about 285° C., and water. The pigment synergist comprises a pigment of the formula (I): where each of R1 to R10 is each independently selected from H, carboxylate, and/or a sulphonate group.