A Flash animation or Flash cartoon is an animated film which is created using Adobe Flash or similar animation software and often distributed in the .swf file format. The term Flash animation not only refers to the file format but to a certain kind of movement and visual style which, in many circles, is seen as simplistic or unpolished. However, with dozens of Flash animated television series, countless more Flash animated television commercials, and award-winning online shorts in circulation, Flash animation is enjoying a renaissance.

In the late 1990s, when for most Internet users, bandwidth was still at 56 kbit/s, many Flash animation artists employed limited animation or cutout animation when creating projects intended for web distribution. This allowed artists to release shorts and interactive experiences well under 1 MB, which could stream both audio and high-end animation. One example is the first episode of The Goddamn George Liquor Program released in 1999, rendered at only 628kB.

Some hallmarks of poorly-produced Flash animation are jerky natural movements (seen in walk-cycles and gestures), auto-tweened character movements, lip-sync without interpolation, and abrupt changes from front to profile view. Although Flash is able to integrate bitmaps and other raster-based art, as well as video, most Flash films are created using only vector-based drawings which often result in a somewhat clean graphic appearance.

Flash animations are typically distributed by way of the World Wide Web, in which case they are often referred to as Internet cartoons, online cartoons, or webtoons. Web Flash animations may be interactive and are often created in a series. A Flash animation is distinguished from a Webcomic, which is a comic strip distributed via the Web, rather than an animated cartoon.