In the title compound, C15H11BrN4OS, the least-squares plane through the 5-bromo-isatin fragment forms a dihedral angle of 13.63 (14)° with the phenyl ring. The mol-ecular conformation features intra-molecular N-H⋯N and N-H⋯O hydrogen bonds. In the crystal, mol-ecules are connected via pairs of N-H⋯O inter-actions into centrosymmetric dimers. Additionally, π-π stacking inter-actions link mol-ecules into chains parallel to the a axis with short C⋯C distances being observed between the phenyl and thio-carbonyl [3.236 (8) Å] groups and between the thio-carbonyl and carbonyl [3.351 (4) Å] groups of stacked mol-ecules.