Trex may refer to:
- Tyrannosaurus rex, a large species of theropod dinosaur from the late Cretaceous Period
- Trex Company, Inc., a composite decking manufacturer
- Tampere Region Exchange, an Internet Exchange Point in Finland
- Trex (card game) a card game
- TREX search engine, a search engine in SAP NetWeaver
- TREX (Tree Regular Expressions for XML), a subset of Regular Language description for XML
- The proteins TREX1 and TREX2
See also
- T. rex (disambiguation)
- Regulatory T cell, commonly abbreviated as "Tregs"