The title compound, C(14)H(11)BrN(2)OS, was synthesized by the reaction of 1,2-benzothia-zol-3(2H)-one with formalin and 3-bromo-aniline in ethanol. The 1,2-benzothia-zolone ring system is approximately planar [maximum deviation = 0.0142 (s.u.?) Å] and forms a dihedral angle of 79.19 (5)° with the benzene ring. In the crystal, molecules are linked by N-H⋯O, C-H⋯O and C-H⋯Br interactions.