In extremis or extremis may refer to:
- In extremis, a Latin phrase meaning "in the farthest reaches" or "at the point of death"
- In Extremis (album), a 1998 album by Thinking Plague
- In extremis (film), a 2000 film by Ettienne Faure
- In Extremis (play), a 2006 play by Howard Brenton
- "Extremis" (comics), an Iron Man story arc
- Extremis: Drop Ride to Doom, an attraction at the London Dungeon