An ink composition is disclosed which includes carbon black; at least one selected from the group consisting of a cyan pigment and a magenta pigment; at least one selected from the group consisting of polyvinyl pyrrolidone, polyvinyl alcohol, and polyethylene glycol, at a ratio of 0.01% by mass or higher but lower than 1.00% by mass, relative to the total amount of the composition; water-insoluble or substantially water-insoluble resin particles, water-insoluble or substantially water-insoluble wax particles or any mixture thereof; and water. An ink set and an image forming method are also disclosed.