In the title compound, [OsBr(C10H14)(C7H5O2)], the central OsII ion is ligated by a hexahaptic η6 p-cymene ring, a Br− ligand and two O atoms of a chelating tropolonate group. The p-cymene ligand presents more than one conformation, giving rise to a discrete disorder, which was modelled with two different orientations with occupancy values of 0.561 (15) and 0.439 (15). The crystal packing features C—H...O and C—H...Br hydrogen bonding. Aromatic π–π stacking interactions are also observed between adjacent non-benzenoid aromatic tropolone rings.