M61 or M-61 may refer to:
In transportation: M61 motorway, a motorway in England M-61 (Michigan highway), a state highway in Michigan M61, a class of locomotives built by NOHAB
In science: Messier 61 (M61), a spiral galaxy in the Virgo Cluster
In firearms and military equipment: M61 Vulcan, a rotary cannon developed for the United States Armed Forces and used in fighter aircraft and other applications M61 (grenade), a fragmentation hand grenade used by the United States Armed Forces M61 Skorpion, a Yugoslav designation for the CZ-Scorpion pistol M61 gas mask, a gas mask used by the Finnish Defence Forces of which three variants were made