| State: | GU |
| Type: | GU |
| Route: | 18 |
| Map Custom: | yes |
| Map Notes: | GH-18 highlighted in red |
| Maint: | Guam Department of Public Works |
| Direction A: | East |
| Terminus A: | in Piti |
| Direction B: | West |
| Terminus B: | Dead end at Drydock Island |
| Previous Type: | GU |
| Previous Route: | 17 |
| Next Type: | GU |
| Next Route: | 26 |
| Length Km: | 2.3 |
Guam Highway 18 (GH-18) is one of the primary automobile highways in the United States territory of Guam.
In spite of its main highway designation, GH-18 is a short spur route, running westward from GH-1 across from the Guam Veterans Cemetery and along onto Drydock Island, a small peninsula located in the middle of Apra Harbor and just to the south of Cabras Island. This peninsula forms the northern edge of Sasa Bay; its south edge is formed by Polaris Point, a Naval site. The waters of Sasa Bay are a marine preserve, making the peninsula a tourist attraction.[1] The peninsula is home to the Marianas Yacht Club, several public beaches, and an Atlantis tourist submarine. Route 18 ends at a dead-end at the west edge of the peninsula.[2]