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