HFO

HFO may refer to:


 * HealthForceOntario
 * Heavy fuel oil
 * Hybrid fibre-optic
 * Hydrofluoroolefin, a refrigerant
 * Hydrous ferric oxides
 * Hypofluorous acid
 * Halbleiterwerk Frankfurt (Oder)
 * High-frequency oscillations
 * Hardy Family Office, a professional wrestling stable led by Matt Hardy