TCG may stand for:
- Geocentric Coordinate Time
- Test call generator, piece of equipment used for testing in the telecommunications industry
- TCG (album), a 2007 album from The Cheetah Girls
- Teleport Communications Group, later acquired by AT&T
- The Catholic Guy, a radio talk show currently airing on Sirius XM Satellite Radio in the U.S.
- Theatre Communications Group
- Timecode generator
- Topps Chewing Gum, the former name of The Topps Company, Inc., a producer of sports cards
- Trading card game
- Trusted Computing Group, an initiative started by AMD, Hewlett-Packard, IBM, Intel, and Microsoft
- Türkiye Cumhuriyeti Gemisi, ship prefix for Ship of the Turkish Republic