Raymond Jon Tester (born August 21, 1956) is an American politician and farmer who served from 2007 to 2025 as a United States senator from Montana and from 2005 to 2007 as president of the Montana Senate. A member of the Democratic Party, he is the most recent Democrat to hold statewide or congressional office in Montana. Tester served in the Montana Senate from 1999 to 2007. He is currently a political analyst for MSNBC.

Tester was first elected to the U.S. Senate in 2006, defeating Republican incumbent Conrad Burns in one of the closest Senate races of that year. He narrowly won reelection in 2012 and 2018. He ran for reelection to a fourth term in 2024, losing to Republican nominee Tim Sheehy.

During his time in office, Tester voted for the Economic Growth, Regulatory Relief, and Consumer Protection Act, which rolled back parts of the Dodd–Frank Act, and joined Republicans in supporting a measure to delay certain environmental regulations affecting coal power plants. He voted against the DREAM Act and against Democratic proposals to expand background checks, and has supported efforts to loosen restrictions on gun exports. Tester supported abortion rights, voted for the Affordable Care Act, and voted for the Respect for Marriage Act.