| Election Name: | 1946 United States Senate election in Montana |
| Country: | Montana |
| Flag Year: | 1905 |
| Type: | presidential |
| Previous Election: | 1940 United States Senate election in Montana |
| Previous Year: | 1940 |
| Next Election: | 1952 United States Senate election in Montana |
| Next Year: | 1952 |
| Election Date: | November 5, 1946 |
| Image1: | Zales Nelson Ecton.jpg |
| Nominee1: | Zales Ecton |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 101,901 |
| Percentage1: | 53.47% |
| Nominee2: | Leif Erickson |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 86,476 |
| Percentage2: | 45.38% |
| Map Size: | 300px |
| U.S. Senator | |
| Before Election: | Burton K. Wheeler |
| Before Party: | Democratic Party (United States) |
| After Election: | Zales Ecton |
| After Party: | Republican Party (United States) |
The 1946 United States Senate election in Montana took place on November 5, 1946. Incumbent United States Senator Burton K. Wheeler, who was first elected to the Senate in 1922, and was re-elected in 1928, 1934, and 1940, ran for re-election. He was challenged in the Democratic primary by Leif Erickson, the Chief Justice of the Montana Supreme Court, and, following a close election, was narrowly defeated by Erickson. In the general election, Erickson faced State Senator Zales Ecton, the Republican nominee. Ultimately, Ecton defeated Erickson by a fairly wide margin, winning his first and only term in the Senate. Another Republican would not be elected Senator from Montana until 42 years later, when Conrad Burns narrowly won the 1988 election.