The British Rail Class 185 Desiro is a class of diesel-hydraulic multiple-unit (DHMU) passenger trains built by Siemens Transportation Systems in Germany for the train operating company First TransPennine Express. They are currently operated by TransPennine Express.

The Siemens Desiro is a family of diesel or electric multiple unit passenger trains developed by Siemens Mobility, a division of the German Siemens AG conglomerate. The main variants are the Desiro Classic, Desiro ML, Desiro UK and the later Desiro City, Desiro HC and Desiro RUS. The trains are mostly used for commuter and regional services, and their rapid acceleration makes them suitable for services with short distances between stations. The design is flexible, and has become common in many European countries.