Thomas Jonathan Ossoff (born February 16, 1987) is an American politician serving as the senior United States senator from Georgia since 2021. A member of the Democratic Party, Ossoff was previously a documentary filmmaker and investigative journalist.

Born in Atlanta to a Jewish father and an Australian mother, Ossoff was the Democratic nominee in the 2017 special election for Georgia's 6th congressional district, which had long been considered a Republican stronghold. The special election proved competitive. It generated national attention, and became the most expensive House election in U.S. history. Ossoff narrowly lost the race to former Georgia Secretary of State Karen Handel.

In 2020, Ossoff won the Democratic nomination for the 2020 U.S. Senate election in Georgia to run against then-incumbent Republican senator David Perdue. Neither candidate reached the 50 percent threshold on the November 3 general election, triggering a runoff election on January 5, 2021, which Ossoff won. Ossoff serves alongside fellow Democrat Raphael Warnock, who defeated incumbent Republican Kelly Loeffler in the 2020 Senate special election runoff, also on January 5, 2021. The two races attracted significant national attention and spending, as they decided which party would control the Senate in the 117th Congress. Warnock and Ossoff's victories helped the Democrats attain a 50–50 split in the Senate, which made an effective majority due to the tie-breaking vote of the Vice President, Kamala Harris. He took office on the same day as the Inauguration of Joe Biden on January 20, 2021, ultimately becoming the senior senator from Georgia.

With his victory, Ossoff became the youngest member of the Senate elected since Don Nickles in 1980 as well as the first Jewish member of the Senate from Georgia, the first Jewish senator from the Deep South since Benjamin F. Jonas of Louisiana, who was elected in 1878, the first senator born in the 1980s, and the first millennial United States senator. Warnock and Ossoff are the first Democrats to represent Georgia in the United States Senate since Zell Miller in 2005.