Gizmo or Gismo may refer to:
- Technology
- The Gizmo or "Gizmotron", an effect unit for the electric guitar
- Gizmo key, found on certain flutes
- Gizmo5, a peer-to-peer Internet telephony and instant messaging software application
- Gizmo, an OpenGL compiler used in Wavemetrics IGOR Pro software
- Gizmo, a bounding box used for manipulating objects in 3D modeling computer programs
- Gizmos, the name of interactive online simulations for math and science education from ExploreLearning
- A gadget, a small device with a particular function
- Gizmo, a 1996-2001 digital game distribution platform by Mplayer.com
- Entertainment
- The Gizmos, a 1970s proto-punk band from Indiana
- Gizmo Williams, a former kick returner in Canadian Football
- Gizmo!, a 1977 documentary film directed by Howard Smith
- Gadgets and Gizmos, a Canadian television show about technological devices
- Gizmo, a character in the comic strip Beetle Bailey
- Gizmo, an Italian band formed in 2005 by Stewart Copeland
- Fiction
- Gizmo (comics), a member of the H.I.V.E. Five in the Teen Titans animated series
- Gizmo (comic book), a 1986 comic book series created by Michael Dooney
- Gizmo Duck, a character in the DuckTales series
- Gizmo, a main character in the films Gremlins and Gremlins 2: The New Batch
- Don Gizmo, a character in the Fallout computer game
- The Gizmo, a four-book series written by Australian author Paul Jennings