Flash Video（简称FLV），是一种网络视频格式，用作串流媒体格式，它的出现有效地解决了视频文档导入Flash后，使导出的SWF文档体积庞大，不能在网络上有效使用等缺点。

一般FLV文档包在SWF PLAYER的壳里，并且FLV可以很好的保护原始地址，不容易被下载到，从而起到保护版权的作用。但还是有些视频格式转换软件将FLV转成一般的视频格式，如中国的软件格式工厂。随着视频网站的丰富，在2008年时这个格式已经非常普及，包括YouTube、NICONICO动画、Google Video、Yahoo! Video、MySpace，以及中国的优酷、酷6等大部分视频分享网站均采用这个格式。

Flash Video is a container file format used to deliver video over the Internet using Adobe Flash Player version 6 and newer. Flash Video content may also be embedded within SWF files. There are two different video file formats known as Flash Video: FLV and F4V. The audio and video data within FLV files are encoded in the same manner as they are within SWF files. The F4V file format is based on the ISO base media file format and is starting with Flash Player 9 update 3. Both formats are supported in Adobe Flash Player and developed by Adobe Systems. FLV was originally developed by Macromedia.