António Manuel de Oliveira Guterres (; European Portuguese: [ɐ̃ˈtɔnju ɡuˈtɛʁɨʃ]; born 30 April 1949) is a Portuguese politician and diplomat. Since 2017, he has served as secretary-general of the United Nations, the ninth person to hold this title. A member of the Portuguese Socialist Party, Guterres served as prime minister of Portugal from 1995 to 2002.

Guterres served as secretary-general of the Socialist Party from 1992 to 2002. He was elected prime minister in 1995 and resigned in 2002, after his party was defeated in the 2001 Portuguese local elections. After six years governing without an absolute majority and with a poor economy, the Socialist Party did worse than expected because of losses in Lisbon and Porto, where polls indicated they had a solid lead. Eduardo Ferro Rodrigues assumed the Socialist Party leadership, but the general election was lost to the Social Democratic Party, led by José Manuel Barroso. Despite this defeat, polling of the Portuguese public in both 2012 and 2014 ranked Guterres the best prime minister of the previous 30 years.He served as president of the Socialist International from 1999 to 2005, and was the United Nations High Commissioner for Refugees from 2005 to 2015. Guterres was elected secretary-general in October 2016, succeeding Ban Ki-moon at the beginning of the following year and becoming the first European to hold this office since Kurt Waldheim in 1981.