HSM is a three-letter acronym that may refer to:
- Harakat al-Shabaab Mujahedeen, a Somali insurgent group
- Hardware security module
- Health Systems Management
- Hepatosplenomegaly
- Hierarchical storage management
- Hierarchical state machine
- High School Musical (film series)
- High School Musical, first film
- High School Musical, the soundtrack to the first film
- High School Musical (disambiguation), other uses
- High Speed Machining
- Holy Spirit Movement
- HSM, the IATA code for Horsham Airport, in Australia
- Molde University College (Høgskolen i Molde)
- Hyper Sonic Motor, Sigma's trade name for photo lens focusing technology using ultrasonic motor
- Hollandsche IJzeren Spoorweg-Maatschappij, a now defunct railway company in the Netherlands, and predecessor of the Nederlandse Spoorwegen.