| State: | PR |
| Type: | PR |
| Route: | 138 |
| Alternate Name: | Spanish; Castilian: Avenida Luis Muñoz Marín |
| Length Km: | 2.6 |
| Direction A: | South |
| Terminus A: | San Ildefonso |
| Junction: | in San Ildefonso |
| Direction B: | North |
| Terminus B: | in Pasto |
| Municipalities: | Coamo |
| Previous Type: | Sec |
| Previous Route: | 137 |
| Next Type: | Urban |
| Next Route: | 139 |
Puerto Rico Highway 138 (PR-138) is a north–south bypass located west of downtown Coamo, Puerto Rico.[1] This road extends from PR-155 to the junction of PR-14 with PR-153 and is known as Avenida Luis Muñoz Marín.[2]