| Election Name: | 1986 United States Senate election in Iowa |
| Country: | Iowa |
| Flag Image: | Flag of Iowa (xrmap collection).svg |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1980 United States Senate election in Iowa |
| Previous Year: | 1980 |
| Next Election: | 1992 United States Senate election in Iowa |
| Next Year: | 1992 |
| Election Date: | November 4, 1986 |
| Image1: | Chuck Grassley.png |
| Nominee1: | Chuck Grassley |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 588,880 |
| Percentage1: | 66.04% |
| Nominee2: | John Roehrick |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 299,406 |
| Percentage2: | 33.57% |
| Map Size: | 240px |
| U.S. Senator | |
| Before Election: | Chuck Grassley |
| Before Party: | Republican Party (United States) |
| After Election: | Chuck Grassley |
| After Party: | Republican Party (United States) |
The 1986 United States Senate election in Iowa was held November 4, 1986. Incumbent Republican United States Senator Chuck Grassley won re-election to a second term, defeating Democratic nominee, attorney John P. Roehrick in a landslide. This would be the last time that Grassley lost a county until 2010 when Roxanne Conlin flipped Johnson County.