3G2 is a file extension used to store audio and video multimedia content. It is a format developed by the 3GPP2 international standardization organization dedicated to the development of mobile telephony. The most common use for 3G2 files is for their transmission over cellular networks. The material encoding in 3G2 files is based on the MPEG-4 standard.

3G2 files can also be used to store multimedia data in mobile phones. They are also supported by QuickTime Player.