A25, A 25 or A-25 may refer to:
- Aero A.25, a Czech military training aircraft of the 1920s
- HLA-A25, an HLA-A serotype
- Junkers A 25, a German two-seater cantilever monoplane
- Article 25, a UK development and disaster relief charity
- A25 accident report form formerly used by the Fleet Air Arm and featured in a World War II song