| Election Name: | 1978 United States Senate election in Wyoming |
| Country: | Wyoming |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1972 United States Senate election in Wyoming |
| Previous Year: | 1972 |
| Next Election: | 1984 United States Senate election in Wyoming |
| Next Year: | 1984 |
| Election Date: | November 7, 1978 |
| Image1: | File:Alan Kooi Simpson (cropped).jpg |
| Nominee1: | Alan Simpson |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 82,908 |
| Percentage1: | 62.17% |
| Nominee2: | Raymond B. Whitaker |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 50,456 |
| Percentage2: | 37.83% |
| Map Size: | 255px |
| U.S. Senator | |
| Before Election: | Clifford Hansen |
| Before Party: | Republican Party (United States) |
| After Election: | Alan K. Simpson |
| After Party: | Republican Party (United States) |
The 1978 United States Senate election in Wyoming was held on November 7, 1978. Incumbent Republican Senator Clifford Hansen declined to seek a third term in office. Former State Representative Alan K. Simpson, the son of former Senator Milward Simpson, won a contested Republican primary and faced Raymond B. Whitaker, the 1960 Democratic nominee for the Senate, in the general election. Despite a favorable environment for Republicans nationwide, Simpson's performance decreased considerably from Hansen's 1972 landslide. Nonetheless, he easily defeated Whitaker, winning 62% of the vote to Whitaker's 38%.