A colored resin particle dispersion containing colored resin particles and water, in which the colored resin particles contain an oil-soluble dye and a polymer P containing a structural unit represented by Formula (1), a structural unit represented by Formula (2), and a hydrophilic group, an ink, an ink set, and an inkjet printing method. L 1 represents a chain hydrocarbon group having 4 to 10 carbon atoms, two ∗ 1's each represent a bonding position, L 2 represents a chain hydrocarbon group having 2 to 25 carbon atoms which may contain an oxygen atom or the like, or a polymer chain having a number-average molecular weight of 500 or greater, Y 1 and Y 2 each independently represent -O-, -S-, or, -NRz-, Rz represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and two ∗ 2's each represent a bonding position.