In the title compound, C13H19N3S, the methyl-amine substituent is coplanar with the thia-diazole ring to which it is attached [C-N-C-S torsion angle = 175.9 (2)°] and the amine H atom is syn to the thia-diazole S atom. Supra-molecular chains along [101], sustained by N-H⋯N hydrogen bonding, feature in the crystal packing.