The magic lantern, also known by its Latin name laterna magica, is an early type of image projector that used pictures—paintings, prints, or photographs—on transparent plates (usually made of glass), one or more lenses, and a light source. Because a single lens inverts an image projected through it (as in the phenomenon which inverts the image of a camera obscura), slides were inserted upside down in the magic lantern, rendering the projected image correctly oriented.

It was mostly developed in the 17th century and commonly used for entertainment purposes. It was increasingly used for education during the 19th century. Since the late 19th century, smaller versions were also mass-produced as toys. The magic lantern was in wide use from the 18th century until the mid-20th century when it was superseded by a compact version that could hold many 35 mm photographic slides: the slide projector.