FES or Fes may refer to:
- Fes or Fez, a city in Morocco
- Fès Roland & Fès Begon, or Fez Roland & Fez Begon, hamlets of Moissac-Vallée-Française, canton of Saint-Germain-de-Calberte, arrondissement of Florac, department of Lozère, France (maybe remembering a battle of Pepin the Short against Septimania located Muslims).
- Feline sarcoma oncogene, a human gene that encodes the feline sarcoma oncogene enzyme
- FES (Ayase Kishimoto), a fictional singer from Chaos;Head anime series and alias of Yui Sakakibara for her songs from Chaos;Head and Steins;Gate anime series
- The Famous Entrepreneurs Series, a business membership club
- Flywheel energy storage, an energy storage method
- Friedrich Ebert Foundation (German: Friedrich Ebert Stiftung)
- Forschung und Entwicklung von Sportgeraten
- Fuerzas Especiales, the special forces of the Mexican Navy
- Functional electrical stimulation, a neurological treatment technique
- Iron(II) sulfide or FeS, a chemical compound
- Persona 3 FES, an add-on disk for Shin Megami Tensei: Persona 3
- Fat Embolism Syndrome, a disease caused by fat emboli arising from fractured bones.
- Flat Earth Society, a group that believes the Earth is flat.