| Election Name: | 1988 United States Senate election in Washington |
| Country: | Washington |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1983 United States Senate special election in Washington |
| Previous Year: | 1983 (special) |
| Next Election: | 1994 United States Senate election in Washington |
| Next Year: | 1994 |
| Election Date: | November 8, 1988 |
| Image1: | Slade Gorton, official Senate photo portrait.jpg |
| Nominee1: | Slade Gorton |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 944,359 |
| Percentage1: | 51.09% |
| Nominee2: | Mike Lowry |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 904,183 |
| Percentage2: | 48.91% |
| Map Size: | 275px |
| U.S. Senator | |
| Before Election: | Daniel J. Evans |
| Before Party: | Republican Party (United States) |
| After Election: | Slade Gorton |
| After Party: | Republican Party (United States) |
The 1988 United States Senate election in Washington was held on November 8, 1988. Incumbent Republican U.S. Senator Daniel J. Evans decided to retire instead of running for re-election to a full term, after being appointed to the seat in 1983, and won election to a partial term that same year. Republican former U.S. Senator Slade Gorton, who had just lost a re-election bid in 1986, won the open seat.[1] As of, this is the last time Washington simultaneously voted for different parties for President and for Senate, as Democrat Michael Dukakis won the state in the concurrent presidential election.