Molybdenum(III) bromide is the inorganic compound with the formula MoBr<sub>3</sub>. It is a black solid that is insoluble in most solvents but dissolves in donor solvents such as pyridine.
Molybdenum(III) bromide is produced by the reaction of elemental molybdenum and bromine at .
It can also be prepared from the reduction of molybdenum(IV) bromide with molybdenum metal, hydrogen gas, or a hydrocarbon.
It has a structure consisting of infinite chains of face-sharing octahedra with alternatingly short and long Mo-Mo contacts. The same structure is adopted by the tribromides of ruthenium and technetium. In contrast, in the high temperature phase of titanium(III) iodide, the Ti---Ti separation is invariant.