Siim Kallas (October 2, 1948 – August 22, 2026) was an Estonian politician who served as Prime Minister of Estonia from 2002 to 2003 and as a European Commissioner from 2004 to 2014.
From 1972 to 1990 Kallas was a member of the Communist Party of the Soviet Union. He worked in the finance ministry of Estonian SSR and was the director of the Estonian branch of State Labor Savings Banks System in 1986–1989. In 1987, Kallas was one of the authors of the IME plan for self-managing Estonia with Tiit Made, Edgar Savisaar, and Mikk Titma. The plan proposed to make Estonia economically independent from the Soviet Union – adopting a market economy and establishing Estonia's own currency and tax system. Kallas was the chief editor of Rahva Hääl, the official newspaper of the Communist Party of Estonia, in 1989–1991. He was elected a member of the Congress of People's Deputies of the Soviet Union in the 1989 Soviet Union legislative election, the first partially free elections in the Soviet Union.
After Estonia restored its independence in 1991, Kallas was appointed the President of the Bank of Estonia, which at the time had only 11 employees. Within a year a coherent structure of the bank was set up and on 20 June 1992, Estonia's own currency, the kroon, was back in circulation for the first time since 1941.
Kallas entered politics in 1994 as one of the founders of liberal Estonian Reform Party, which was successful in the 1995 parliamentary elections. Kallas served as the minister of foreign affairs from 1995 to 1996. He later served as the minister of finance from 1999 to 2002 and the prime minister from 2002 to 2003.
He served as the European Commissioner for Transport between 2010 and 2014. Before that he was the European Commissioner for Administrative Affairs, Audit and Anti-Fraud between 2004 and 2009. In both Barroso Commissions he was also a Vice-President. He was twice appointed the Acting Commissioner for Economic and Monetary Affairs and the Euro in Olli Rehn's stead, from 19 April 2014 to 25 May 2014 while he was on electoral campaign leave for the 2014 elections to the European Parliament and from 1 July 2014 to 16 July 2014 after he took up his seat.
After leaving the European Commission, Kallas ran in the Estonian presidential election in 2016, but was not elected. In October 2017, he started as the municipal mayor of Viimsi Parish. In 2019 he was elected member of the Riigikogu, a post he was also elected to in 2023. He resigned as a member of Riigikogu and from politics in September 2024.
His daughter, Kaja Kallas, was the prime minister of Estonia from 2021 to 2024.
