DFO can refer to:
- Divisional Forest Officer, a rank of an officer in the Indian Forest Service
- Deadly Fixed Object, an object in the Right-of-way, that because of its size or construction poses a risk to motor vehicles
- Department of Fisheries and Oceans, also called Fisheries and Oceans Canada
- 1,8-Diazafluoren-9-one, a chemical that makes fingerprints glow when lit by laser or blue-green light
- Direct Factory Outlets, warehouse-style outlet malls in a number of locations in Australia
- Director of Flight Operations, a rank in airline organization
- Dungeon Fighter Online, a beat 'em up game published by Nexon
- Deferoxamine, a bacterial siderophore produced by the actinobacteria Streptomyces pilosus that has medical applications as a chelating agent used to remove excess iron from the body.