An ink set comprising: an ink composition which contains a colorant and water; and a treatment liquid which contains water-insoluble resin particles having a constitutional unit derived from a first monomer that contains at least one group selected from a sulfo group and a salt of the sulfo group and a constitutional unit derived from a second monomer that contains at least one structure selected from an aromatic ring structure and an alicyclic structure, a compound that causes the colorant in the ink composition to aggregate, and water, wherein the constitutional unit derived from the second monomer is at least one constitutional unit selected from the group of constitutional units represented by any of Formulae A to E, and wherein at least one constitutional unit derived from the second monomer includes a constitutional unit represented by Formula A, wherein in the formulae, R 11 represents a methyl group or a hydrogen atom, R 12 represents a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, n represents an integer of 0 to 5, and in a case where n represents 2 or greater, a plurality of R 12 's may be the same as or different from each other, and L 11 represents a divalent linking group formed by linking one or two or more groups selected from the group consisting of a single bond, a linear, branched, or cyclic alkylene group having 1 to 18 carbon atoms, an arylene group having 6 to 18 carbon atoms, -O-, -NH-, -S-, and -C(=O)-, wherein the compound that causes the colorant in the ink composition to aggregate is a polyvalent metal salt or a cationic compound an ink composition which contains a colorant and water; and a treatment liquid which contains water-insoluble resin particles having a constitutional unit derived from a first monomer that contains at least one group selected from a sulfo group and a salt of the sulfo group and a constitutional unit derived from a second monomer that contains at least one structure selected from an aromatic ring structure and an alicyclic structure, a compound that causes the colorant in the ink composition to aggregate, and water, wherein the constitutional unit derived from the second monomer is at least one constitutional unit selected from the group of constitutional units represented by any of Formulae A to E, and wherein at least one constitutional unit derived from the second monomer includes a constitutional unit represented by Formula A, wherein in the formulae, R 11 represents a methyl group or a hydrogen atom, R 12 represents a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, n represents an integer of 0 to 5, and in a case where n represents 2 or greater, a plurality of R 12 's may be the same as or different from each other, and L 11 represents a divalent linking group formed by linking one or two or more groups selected from the group consisting of a single bond, a linear, branched, or cyclic alkylene group having 1 to 18 carbon atoms, an arylene group having 6 to 18 carbon atoms, -O-, -NH-, -S-, and -C(=O)-, wherein the compound that causes the colorant in the ink composition to aggregate is a polyvalent metal salt or a cationic compound