Holmium(III) fluoride is an inorganic compound with a chemical formula of HoF<sub>3</sub>.
Holmium(III) fluoride can be produced by reacting holmium oxide and ammonium fluoride, then crystallising it from the ammonium salt formed in solution:
It can also be prepared by directly reacting holmium with fluorine:
Holmium(III) fluoride is a yellowish powder that is insoluble in water. It has an orthorhombic crystal system (corresponding to ò-YF<sub>3</sub>) with the space group Pnma (space group no. 62). However, there is also a trigonal low-temperature form of the lanthanum(III) fluoride type.