The title thio-semicarbazone derivative, C(12)H(18)N(4)S, features intra-molecular N-H⋯N and C-H⋯S hydrogen bonds which generate S(5) ring motifs. The dihedral angle between the benzene ring and the thio-urea unit is 6.30 (6)° indicating planarity in the mol-ecule. Inter-molecular N-H⋯S hydrogen bonds generate dimers with an R(2) (2)(8) ring motif. The methyl group of the N-ethyl residue is disordered and was refined with site occupancies of 0.521 (5) and 0.479 (5).