Sentry may refer to:
- Sentry, a guard at a gate or other point of passage − see also General Orders for Sentries
- Sentry (AUV), Autonomous underwater vehicle used to measure deep-ocean data
- Sentry (monitoring system), an automatic near-Earth asteroid collision monitoring system
- Sentry (comics), the codename of unrelated fictional characters of the Marvel Universe
- Sentry (Robert Reynolds), the most notable of these characters
- Sentry Foods, a chain of grocery stores in Wisconsin, United States
- E-3 Sentry AWACS, airborne early warning aircraft
- Sentry Insurance, a Wisconsin based insurance company
- Sentry Island, Nunavut, Canada
- Sentry gun, a gun that automatically aims and fires at targets
- SentrySafe, a safe manufacturing company headquartered in Rochester, New York
- The Sentinel (video game), released in the US as The Sentry
- Soviet frigate Storozhevoy, (name translates to The Sentry in English)
- Sentry Group Motivating Success Canadian based Financial Consulting firm