| Stuart Island Marine State Park | |
| Map: | USA Washington#USA |
| Relief: | 1 |
| Location: | San Juan County, Washington, United States |
| Coordinates: | 48.6764°N -123.2°W |
| Area Acre: | 433 |
| Elevation: | 89feet |
| Designation: | Washington marine state park |
| Established: | 1952 |
| Website: | Stuart Island Marine State Park |
Stuart Island State Park in San Juan County, Washington is a marine camping park in the Washington State Park System. It consists of of land and waterways on and around Stuart Island, named for Frederick D. Stuart, clerk to explorer Charles Wilkes.
The park has 33030feet of saltwater shoreline with moorage at Reid Harbor and Prevost Harbor. Activities include hiking on of trails, boating, scuba diving, fishing, and crabbing. The park is part of the Cascadia Marine Trail; some of its 18 primitive campsites are reserved for boaters arriving by other than motorized means.