UDP-based Data Transfer Protocol (UDT), is a high-performance data transfer protocol designed for transferring large volumetric datasets over high-speed wide area networks. Such settings are typically disadvantageous for the more common TCP protocol.

Initial versions were developed and tested on very high-speed networks (1 Gbit/s, 10 Gbit/s, etc.); however, recent versions of the protocol have been updated to support the commodity Internet as well. For example, the protocol now supports rendezvous connection setup, which is a desirable feature for traversing NAT firewalls using UDP.

UDT has an open source implementation which can be found on SourceForge. It is one of the most popular solutions for supporting high-speed data transfer and is part of many research projects and commercial products.