M41, M-41, or M.41 may refer to:
Transportation M-41 (Michigan highway), a former state highway in Michigan M41 (Cape Town), a Metropolitan Route in Cape Town, South Africa M41 (Johannesburg), a Metropolitan Route in Johannesburg, South Africa M41 (Durban), a Metropolitan Route near Durban, South Africa M41 motorway, a motorway in England M41 highway, a major highway in Central Asia which crosses the Pamir Mountains BMW M41, a 1994 straight-4 diesel engine
Military
M41 Walker Bulldog, an American light tank M41 155 mm howitzer motor carriage, developed from M24 Chaffee M1941 Johnson rifle M1941 Johnson light machine gun Macchi M.41 and M.41bis, an Italian flying boat fighter of the 1930s Type 41 75 mm mountain gun, a Japanese artillery gun , a British naval minesweeper M41 light rifle/TLR-41, a possible designation for the Thompson light rifle M1941 field jacket, a World War II-era US Army uniform jacket
Entertainment M41A pulse rifle, a fictional assault rifle from the 1986 film Aliens and related media The 41st millennium, as expressed in the game Warhammer 40000.
Other
Messier 41 (M41), an open star cluster in the constellation Canis Major M41, a postcode in the M postcode area that covers the town of Urmston, United Kingdom the 41st Mersenne prime