Yüksek Hızlı Tren or YHT (English: High Speed Train) is a high-speed rail service operated by TCDD Transport in Turkey. Branded as "YHT", they are TCDD Transport's flagship passenger train service and the only high-speed rail service in the country. As of 2025, the network spans 1,385 km (860.6 mi) and serves major cities like Istanbul, Ankara, Eskişehir, İzmit, Konya, and Sivas. Expansion of the system is underway and the network is expected to reach Edirne, Afyonkarahisar, Adana, and İzmir in the 2020s.
High-speed rail in Turkey was originally planned to be built as early as 1975, but it wasn't until 2003 that the construction of the Ankara-Istanbul high-speed railway began. The first section was completed in 2007, between Eskişehir and Esenkent with passenger operations beginning on 13 March 2009 between Eskişehir and Ankara. On 23 August 2011, the Turkish State Railways inaugurated its second high-speed railway to Konya and on 25 July 2014, the railway was opened to Istanbul. The State Railways have integrated the YHT network with other projects done in major urban areas. In Ankara, the route was expanded from three tracks to five tracks to allow for frequent Başkentray commuter rail service, along with a new high-speed rail concourse at Ankara station. In Istanbul, YHT trains use the Marmaray Tunnel to traverse the Bosphorus Strait and reach the European side of the city.