| State: | MO |
| Type: | MO |
| Route: | 3 |
| Map Custom: | yes |
| Maint: | MoDOT |
| Length Mi: | 72 |
| Direction A: | North |
| Direction B: | South |
| Terminus A: | south of Kirksville |
| Junction: | near La Plata in Callao in Clifton Hill in Roanoke |
| Terminus B: | north of Fayette |
| Previous Type: | MO |
| Previous Route: | 2 |
| Next Type: | MO |
| Next Route: | 4 |
Route 3 is a highway in northern and central Missouri. Its northern terminus is at Route 11 south of Kirksville; its southern terminus is at Route 5/Route 240 northwest of Fayette.
Route 3 was initially Route 67, designated in 1922 between Rocheport and Fayette. It was renumbered in 1926 due to US 67. In 1934/1935, the route extended north to US 36 in Callao. The next year, the original portion from Rocheport to Fayette became part of Route 240. In 1953/1954, the route extended north to Kirksville, its current terminus.