5F

5F may refer to:

• 5f electrons, of an electron configuration
• The Armageddon Factor (production code: 5F), a 1979 Doctor Who serial
• FlyOne (IATA code: 5F), a Moldovan low-cost airline
• Arctic Circle Air (former IATA code: 5F), a former US-American airline

• 5-Fluoro-AMT (5-F-AMT)
• F5 (disambiguation)