MM1 may refer to:
MM1 (US Navy rating), Machinist's mate First Class MM1 (MMS), a type of Multimedia Messaging Service interface Motocross Madness (1998 video game), a video game developed by Rainbow Studios Midtown Madness, a 1999 racing game developed by Angel Studios M/M/1 model, a single-server queuing model MM/1, the Multi-Media One was a successor to the TRS-80 Color Computer MM1 register, a CPU register used by the MMX extension Mega Man (video game), the first game in the Mega Man video game series Might and Magic Book One: The Secret of the Inner Sanctum, the first game in the Might and Magic video game series Hawk MM-1, semi-automatic grenade launcher Melbourne Metro, Stage 1 a proposed rail tunnel in Melbourne, Australia linking the Domain Interchange to North Melbourne railway station Milan Metro Line 1 (Italian Metropolitana di Milano, linea 1), first underground rapid transit line in Milan, Italy Modigliani–Miller theorem (proposition 1), a theorem on capital structure Line 1 (Mumbai Metro), also known as Mumbai Metro 1