Projector may refer to:
- Image projector, a device that projects an image on a surface
- Video projector, a device that projects a video signal from computer, home theater system etc.
- Movie projector, a device that projects moving pictures from a filmstrip
- Slide projector, a device that projects a still image with a transparent base
- Overhead projector, a device that projects a transparent image
- Opaque projector, a predecessor to the overhead projector
- Planetarium projector, a device that projects images of sky objects
- Magic lantern (projector), a historic projection device
- Camera obscura, the historic ancestor to projection devices
- Enlarger, a device used to produce photographic prints from negatives
- Ceiling projector, a device used to measure the height of clouds
- Projection (linear algebra), a linear transformation of a vector space
- Projector (album), an album by Dark Tranquillity
- A type of mortar (weapon)
- A version control system used in the Macintosh Programmer's Workshop
- As a synonym for promoter, e.g. in the phrase "railway projectors"
- Projector (patent) is an archaic term in US patent law meaning original inventor to reduce an invention to practice.