An election was held November 3, 2020, to elect 25 members to Montana's Senate. The election coincided with elections for other offices, including the presidency, U.S Senate, U.S. House of Representatives, governorship, and state house. The primary election was held on June 2, 2020.
Summary of the November 3, 2020 Montana Senate election results
Districts where the margin of victory was under 10%:
Incumbent Republican Dee Brown had represented the 2nd district since 2013. Brown was term-limited and could not seek re-election. State Representative Carl Glimm won the open seat.
Incumbent Republican Keith Regier had represented the 3rd district since 2017.
Incumbent Republican Albert Olszewski had represented the 6th district since 2017. Olszewski unsuccessfully sought the Republican nomination for Governor. Term-limited state representative and state House Speaker Greg Hertz won the open seat.
Incumbent Republican Jennifer Fielder had represented the 7th district since 2013. Fielder was term-limited and ran successfully for a seat on the Montana Public Service Commission.
Incumbent Steve Fitzpatrick had represented the 10th district since 2017.
Incumbent Republican Ryan Osmundson had represented the 15th district since 2017.
Incumbent Democrat Frank Smith had represented the 16th district since 2017. Smith chose not to seek re-election, and instead successfully ran for a seat in the Montana House.
Incumbent Republican Mike Lang had represented the 17th district since 2017.
Incumbent Republican Steve Hinebauch had represented the 18th district since 2017.
Incumbent Republican Jason Small had represented the 21st district since 2017.
Incumbent Republican Roger Webb had represented the 23rd district since 2013. Webb was term-limited and could not seek re-election. Former state representative Tom McGillvray won the open seat.
Incumbent Democrat Jen Gross had represented the 25th district since 2017.
Incumbent Democrat Margaret MacDonald had represented the 26th district since 2017. She ran for re-election to a 2nd term, but was defeated by Republican Chris Friedel.
Incumbent Republican Tom Richmond had represented the 28th district since 2017. Former Public Service Commissioner and state representative Brad Molnar defeated Richmond in the Republican primary.
Incumbent Democrat Mike Phillips had represented the 31st district since 2013. Phillips was term-limited and could not seek re-election. State Representative Christopher Pope won the open seat.
Incumbent Republican Scott Sales had represented the 35th district and its predecessors since 2013. Sales was term-limited and could not seek re-election, he instead ran Secretary of State.
Incumbent Republican Jeffrey Welborn had represented the 36th district since 2017.
Incumbent Democrat Minority Leader Jon Sesso had represented the 37th district since 2013. Sesso was term-limited and could not seek re-election.
Incumbent Democrat Edith McClafferty had represented the 38th district since 2017.
Incumbent Democrat Gene Vuckovich had represented the 39th district since 2011. Vuckovich was term-limited and could not seek re-election.
Incumbent Republican Terry Gauthier had represented the 40th district since 2017.
Incumbent Republican Majority Leader Fred Thomas had represented the 44th district since 2013. Thomas was term-limited and could not seek re-election. Representative Theresa Manzella won the open seat.
Incumbent Democrat Dick Barrett had represented the 45th district and its predecessors since 2013. Barrett was term-limited and could not seek re-election.
Incumbent Democrat Sue Malek had represented the 46th district since 2013. Malek was term-limited and could not seek re-election.
Incumbent Republican Dan Salomon had represented the 47th district since 2017.