Tumbler may refer to:
- A part of a lock whose position must be changed by a key in order to release the bolt (see also: pin tumbler lock, tubular pin tumbler lock, and disc tumbler lock)
- A flat-bottomed drinking glass made of plastic, glass, or metal (see List of glassware#Tumblers)
- A machine for smoothing or polishing the surface of a solid material (see Tumble polishing)
- Roly-poly toy, a type of toy that can tumble over and then straighten up by itself
- An acrobat
- The button on top of a chess clock
- The pupal stage of a mosquito
- The Tumbler, a vehicle in the Batman trilogy
- Tumbler, A fictional human supervillain and enemy of Captain America
- Tumble dryer (clothes dryer)
- Tumbler (pigeon), a pigeon breed known for their particular flight pattern
- Tumbler (Project Xanadu), in the Xanadu computer system, a unique identifier of a unit of text or an embedded link
- The Tumbler, an album by John Martyn