In the title compound, C12H8BrN3O, the 4-bromo-phenol ring is coplanar with the planar imidazo[4,5-b]pyridine moiety (r.m.s deviation = 0.015 Å), making a dihedral angle of 1.8 (2)°. There is an intra-molecular O-H⋯N hydrogen bond forming an S(6) ring motif. In the crystal, mol-ecules are linked via N-H⋯N and O-H⋯Br hydrogen bonds, forming undulating sheets parallel to (10-2). The sheets are linked by π-π inter-actions [inter-centroid distance = 3.7680 (17) Å], involving inversion-related mol-ecules, forming a three-dimensional structure.