SoS can refer to:
- Scotland on Sunday, a Scottish weekly newspaper.
- Scrum of scrums, a technique to operate scrum at scale. Scrum is a framework within project management for developing, delivering, and sustaining products in a complex environment.
- Son Of Sardaar, a 2012 Indian film.
- "Secret of success", a colloquial phrase with varied interpretations across cultures.[citation needed][vague]
- System of Systems, systems that pool their resources and capabilities together to create a new, more complex system.