M101 or M-101 most often refers to: Messier 101, or the Pinwheel Galaxy, a spiral galaxy M101 howitzer, a 105 mm light howitzer M101 or M-101 may also refer to: Myasishchev M-101T Gzhel, an aircraft produced in Russia Line M101 (Beijing Subway), a metro line under construction in Beijing, scheduled to open in 2027 M101 (New York City bus), a bus route in Manhattan Hammond Organ, a Hammond Spinet Organ M-101 (Michigan highway), a state highway in Michigan HMS Sandown (M101), British naval ship commissioned in 1989, decommissioned in 2005. M-101 German Kriegsmarine minesweeper pt:M101