The 1986–87 United Counties League season was the 80th in the history of the United Counties League, a football competition in England.
| Competition: | United Counties League Premier Division |
| Season: | 1986–87 |
| Winners: | Potton United |
| Promoted: | Baldock Town |
| Relegated: | Ampthill Town |
| Matches: | 420 |
| Total Goals: | 1352 |
| Prevseason: | 1985–86 |
| Nextseason: | 1987–88 |
The Premier Division featured 19 clubs which competed in the division last season, along with two new clubs:
| Competition: | United Counties League Division One |
| Season: | 1986–87 |
| Winners: | Baker Perkins |
| Promoted: | Baker Perkins Cogenhoe United |
| Matches: | 342 |
| Total Goals: | 1134 |
| Prevseason: | 1985–86 |
| Nextseason: | 1987–88 |
Division One featured 18 clubs which competed in the division last season, along with one new club: