| Acronym | Definition |
|---|
| HMCS | Her Majesty's Courts Service (UK) |
| HMCS | Her Majesty's Canadian Ship (Canada) |
| HMCS | Hawaiian Mission Children's Society (est. 1852) |
| HMCS | Harmonised Mandatory Control System |
| HMCS | Her/His Majesty's Canadian Ship |
| HMCS | Senior Chief Hospital Corpsman (Naval Rating) |
| HMCS | Huygens Monitor and Control System (US NASA) |
| HMCS | High Maltose Corn Syrup |
| HMCS | Hydrometrocolpos, Postaxial Polydactyly, and Congenital Heart Malformation |
| HMCS | Helmet Mounting Cueing System |
| HMCS | Her Majesty's Colonial Ship |
| HMCS | His/Her Majesty's Civil Service |