Reactive azo dyes represented by the general formula (I) or (II): ##STR1## wherein M is a hydrogen atom or an alkali metal, R.sup.1 is a hydrogen atom, a chlorine atom, a lower alkyl group, a lower alkoxy group, a nitro group or a carboxyl group, R.sup.2 and R.sup.8 are a lower alkyl group, a lower alkoxy group or a sulfonic acid group, R.sup.3, R.sup.7 and R.sup.9 are a hydrogen atom, a lower alkyl group, a lower alkoxy group, an acetylamino group or a sulfonic acid group, R.sup.4 and R.sup.5 are a hydrogen atom, a methyl group, a methoxy group or a sulfonic acid group, R.sup.6 is a hydrogen atom, a lower alkyl group, a lower alkoxy group or a sulfonic acid group, Z.sup.1 is a chlorine atom, a fluorine atom, an aliphatic or an aromatic amino residual group, a methoxy group or a phenoxy group, Z.sup.2 is the same one as Z.sup.1 when Z.sup.3 is ##STR2## Z.sup.2 is a chlorine atom or a fluorine atom when Z.sup.3 is an aliphatic amino residual group, an aromatic amino residual group except ##STR3## a methoxy group or a phenoxy group, Z.sup.3 is ##STR4## an aliphatic amino residual group, an aromatic amino residual group except ##STR5## a methoxy group, or a phenoxy group, m is 1, 2 or 3, m' is 2 or 3, n is 0 or 1, and the benzene rings A, B and C may be naphthalene rings.