In the title thio-urea derivative, C(16)H(17)N(3)OS, the hy-droxy- and methyl-substituted benzene rings form dihedral angles of 9.62 (12) and 55.69 (6)°, respectively, with the central CN(3)S chromophore (r.m.s. deviation = 0.0117 Å). An intra-molecular O-H⋯N hydrogen bond ensures the coplanarity of the central atoms. The H atoms of the NH groups are syn and the conformation about the N=C double bond [1.295 (4) Å] is E. In the crystal, helical supra-molecular chains sustained primarily by N-H⋯S hydrogen bonds are found. Additional stabilization is provided by C-H⋯π and π-π [ring centroid(hy-droxy-benzene)⋯ring centroid(methyl-benzene) = 3.8524 (18) Å] inter-actions.