XMT can refer to:
- Extensible MPEG-4 Textual Format, an XML-based file format for storing MPEG-4 data in a way suitable for further editing
- Explicit multi-threading, a parallel computing paradigm designed around the Parallel Random Access Machine
- Cray XMT - a multithreaded supercomputing architecture, the successor to the Cray MTA-2.
- 8-hydroxyfuranocoumarin 8-O-methyltransferase, an enzyme