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