M139

M139 could refer to:

• M-139 (Michigan highway)
• Mercedes-Benz M139 engine
• the US Army model number for the Hispano-Suiza HS.820 20 mm autocannon
• the Maserati M139 platform, a front mid-engine, rear-wheel-drive automobile platform
• M139 bomblet, a chemical cluster bomb for launch on a ground-to-ground rocket