| Election Name: | 1974 United States Senate election in Washington |
| Country: | Washington |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1968 United States Senate election in Washington |
| Previous Year: | 1968 |
| Next Election: | 1980 United States Senate election in Washington |
| Next Year: | 1980 |
| Election Date: | November 5, 1974 |
| Image1: | Warren Magnuson (D-WA) (cropped).jpg |
| Nominee1: | Warren Magnuson |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 611,811 |
| Percentage1: | 60.70% |
| Nominee2: | Jack Metcalf |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 363,626 |
| Percentage2: | 36.08% |
| Map Size: | 275px |
| U.S. Senator | |
| Before Election: | Warren G. Magnuson |
| Before Party: | Democratic Party (United States) |
| After Election: | Warren G. Magnuson |
| After Party: | Democratic Party (United States) |
The 1974 United States Senate election in Washington was held on November 5, 1974. Incumbent Democratic U.S. Senator Warren Magnuson won a sixth term in office, defeating Republican state senator Jack Metcalf, in a rematch of the previous election.
The blanket primary was held on September 17, 1974.