HMCS may refer to:
Her Majesty's Courts Service (2005-11) His Majesty's Canadian Ship His Majesty's Colonial Ship, see His Majesty's Ship Senior Chief Hospital Corpsman, a United States Navy rate Hazardous Material Control System (see Workplace Hazardous Materials Information System) HMC Investment Securities Molybdenum cofactor sulfurtransferase, an enzyme High-maltose corn syrup