The title azo mol-ecule, C16H9Br3N2O, adopts a trans conformation with respect to the azo N=N double bond. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. The dihedral angle between the naphthalene ring system and the benzene ring is 33.80 (16)°. In the crystal, mol-ecules are stacked in columns along the a axis by π-π inter-actions [centroid-centroid distances = 3.815 (3) and 3.990 (3) Å].