Zigmantas Balčytis (born 16 November 1953) is a Lithuanian politician who briefly served as acting Prime Minister of Lithuania in 2006. He took office on 1 June 2006 following the resignation of Algirdas Brazauskas, but failed to be approved by the Parliament to become prime minister. He was succeeded on 4 July by Gediminas Kirkilas. Balčytis was a member of the Social Democratic Party of Lithuania (LSDP) until 2021 and was Minister of Finance in the Brazauskas government from 2005 to 2007. On 19 October 2021, Balčytis left the LSDP and joined the newly formed party Union of Democrats "For Lithuania".