Plug-in, plug in or plugin may refer to:
- Plug-in (computing) is a software component that adds a specific feature to an existing computer program.
- Audio plug-in, adds audio signal processing features
- Photoshop plugin, a piece of software that enhances the functionality of Adobe Photoshop
- Plug-in electric vehicle, type of electric vehicle
- Plug-in hybrid, a type of plug-in electric vehicle
- Glade PlugIns, fragrance distribution product
- Plug Ins, chain of electronics stores owned by Al-Futtaim Group
