VP3 is the extension given to files that store streaming video data. It is a compressed format using codecs developed by On2 Technologies Inc. It is a series of video codecs collectively called TrueMotion. This format uses lossy compression. VP3 files can be supported by many movie playback programs, but must have the correct codec installed.

VP3 was replaced by Theora format, and On2 Technologies Inc. was acquired by the Xiph.Org Foundation. VP3 files are rare these days.