M17 or M-17 may refer to:
- M17 road (Ireland)
- M17 road (Bosnia and Herzegovina)
- Highway M17 (Ukraine)
- M-17 (Michigan highway)
- M17 (East London), a Metropolitan Route in East London, South Africa
- M17 (Cape Town), a Metropolitan Route in Cape Town, South Africa
- M17 (Johannesburg), a Metropolitan Route in Johannesburg, South Africa
- M17 (Pretoria), a Metropolitan Route in Pretoria, South Africa
- M17 (Durban), a Metropolitan Route in Durban, South Africa
- M17 (Port Elizabeth), a Metropolitan Route in Port Elizabeth, South Africa
- Myasishchev M-17 Stratosphera (NATO reporting name Mystic-A), an early version of the Myasishchev M-55 reconnaissance aircraft
- Miles M.17 Monarch, a 1936 British, light, touring aeroplane
- M.17, a German World War 1 prototype aircraft, the basis for one of the two Fokker B.II (1916)
- HMS M17, First World War Royal Navy M15-class monitor
- BMW M17, car engine in the M10 family
- M17 agar, Lactococcus growth medium developed in 1971
- M17 or Messier 17, a nebula also called the Omega Nebula, the Swan Nebula, or several other names
- M17 or March 17, 2007 anti-war protest, organized by the ANSWER Coalition
- M17 Project, a free, open-source, digital communication protocol for amateur radio