| Marathon Middle High School | |
| Type: | Public middle school and high school |
| Gender: | Co-educational |
| District: | Monroe County School District |
| Address: | 350 Sombrero Beach Road |
| City: | Marathon |
| State: | Florida |
| Zipcode: | 33050 |
| Country: | U.S. |
| Coordinates: | 24.7041°N -81.0781°W |
| Established: | 1957 |
| Enrollment: | 707 (2022–23) |
| Teaching Staff: | 45.00 (FTE) (2022–23) |
| Ratio: | 15.71 (2022–23) |
| Grades: | 6–12 |
| Campus: | Remote town |
| Principal: | Christine Paul[1] |
| Superintendent: | Theresa Axford[2] |
| Mascot: | Dolphins |
| Conference: | FHSAA Division 32, District 18 |
| Newspaper: | Dolphin Pride |
Marathon Middle High School is a public middle school and high school in Marathon, Florida in the Florida Keys. It is within the Monroe County School District.