| State: | KY |
| Type: | KY |
| Route: | 166 |
| Maint: | KYTC |
| Map Custom: | yes |
| Map Notes: | KY 166 highlighted in red |
| Length Mi: | 13.279 |
| Length Round: | 3 |
| Length Ref: | [1] |
| Direction A: | West |
| Terminus A: | near Hickman |
| Junction: | in Fulton |
| Direction B: | East |
| Terminus B: | in Fulton |
| Counties: | Fulton |
| Previous Type: | KY |
| Previous Route: | 165 |
| Next Type: | KY |
| Next Route: | 167 |
Kentucky Route 166 (KY 166) is a 13.279miles state highway in Fulton County, Kentucky. It runs from Kentucky Route 125 southeast of Hickman to U.S. Route 45 and Kentucky Route 1648 in northwestern Fulton.