M45 or variants may refer to: Military equipment Carl Gustaf m/45, a 9×19mm Swedish submachine gun M45, a variant of the M26 Pershing heavy/medium tank of the United States Army Madsen M1945, a 9x19mm Danish submachinegun, also referred to as the M45 M45 (missile), a French Navy submarine-launched ballistic missile M45 Quadmount, a weapon mounting consisting of four "heavy barrel" .50 caliber M2 Browning machine guns MEU(SOC) pistol (also M45 MEUSOC), a magazine-fed, recoil-operated, single-action, semiautomatic pistol M45, a gas mask currently issued in the United States
Transport Infiniti M45, a rebadged Japanese-spec Nissan Gloria of the Infiniti M line M-45 (Michigan highway), a state trunkline highway in the US state of Michigan M-45 (Spain), a highway bypass built in the Community of Madrid of regional importance M45 (Cape Town), a Metropolitan Route in Cape Town, South Africa M45 (Johannesburg), a Metropolitan Route in Johannesburg, South Africa M45 (Durban), a Metropolitan Route in Durban, South Africa M45 motorway, a motorway in Northamptonshire and Warwickshire, England
Other M 45, an age category of masters athletics M45, a single-nucleotide polymorphism that is a component of Haplogroup P1 Pleiades (designation Messier 45 or M45), an open star cluster containing middle-aged, hot B-type stars Yahoo M45, a computer cluster announced in November 2007 by Yahoo