Yekaterinburg ( yih-KAT-ər-in-burg; Russian: Екатеринбург, IPA: [jɪkətʲɪrʲɪnˈburk]), alternatively romanized as Ekaterinburg and formerly known as Sverdlovsk (Russian: Свердло́вск, IPA: [svʲɪrˈdlofsk], 1924–1991), is a city and the administrative centre of Sverdlovsk Oblast and the Ural Federal District, Russia. The city is located on the Iset River between the Volga-Ural region and Siberia, with a population of roughly 1.5 million residents, up to 2.2 million residents in the urban agglomeration. Yekaterinburg is the fourth-largest city in Russia, the largest city in the Ural Federal District, and one of Russia's main cultural and industrial centres. Yekaterinburg has been dubbed the "Third capital of Russia", as it is ranked third by the size of its economy, culture, transportation and tourism.

Yekaterinburg was founded on 18 November 1723 and named after Yekaterina I, the wife of Russian emperor Peter the Great. The city served as the mining capital of the Russian Empire as well as a strategic connection between Europe and Asia. In 1781, Catherine the Great gave Yekaterinburg the status of a district town of Perm Province, and built the historical Siberian Route through the city. Yekaterinburg became a key city to Siberia, which had rich resources. In the late 19th century, Yekaterinburg became one of the centres of revolutionary movements in the Urals. In 1924, after the Russian SFSR founded the Soviet Union, the city was renamed Sverdlovsk after the Bolshevik leader Yakov Sverdlov. During the Soviet era, Sverdlovsk was turned into an industrial and administrative powerhouse. In 1991, after the dissolution of the Soviet Union, the city returned to its historical name.

Yekaterinburg is one of Russia's most important economic centres and was one of the host cities of the 2018 FIFA World Cup. The city is currently experiencing an economic and population boom, which resulted in some of the tallest skyscrapers of Russia being located in the city. Yekaterinburg is home to the headquarters of the Central Military District of the Russian Armed Forces, as well as the presidium of the Ural Branch of the Russian Academy of Sciences.

Yekaterinburg is famous for its constructivist architecture and is also considered the "Russian capital of street art".