Dual County League
The Dual County League is a dual county high school athletic conference in District 4 of the Massachusetts Interscholastic Athletic Association. The conference serves schools from Middlesex County and Suffolk County
Schools/Divisions
The following eleven schools are a member of the Dual County League.| School | Location | Colors | Type | Year founded | Enrollment | Nickname |
| Acton-Boxborough Regional High School | Acton, Massachusetts | Blue & Gold | public secondary | 1955 | 1,951 | Revolution |
| Bedford High School | Bedford, Massachusetts | Blue | public secondary | 1955 | 829 | Buccaneers |
| Boston Latin School | Boston, Massachusetts | Purple | public exam secondary | 1635 | 2,383 | Wolfpack |
| Cambridge Rindge and Latin School | Cambridge, Massachusetts | Black & Silver | public secondary | 1648 | 1,836 | Falcons |
| Concord-Carlisle High School | Concord, Massachusetts | Maroon & Gold | public secondary | 1852 | 1,300 | Patriots |
| Lincoln-Sudbury Regional High School | Sudbury, Massachusetts | Navy Blue & Red | public secondary | 1954 | 1,641 | Warriors |
| Newton South High School | Newton, Massachusetts | Blue & Orange | public secondary | 1960 | 1,740 | Lions |
| Waltham High School | Waltham, Massachusetts | Red | public secondary | 1968 | 1,375 | Hawks |
| Wayland High School | Wayland, Massachusetts | Orange & Black | public secondary | 1854 | 870 | Warriors |
| Westford Academy | Westford, Massachusetts | Maroon & Grey | public secondary | 1792 | 1,651 | Ghosts |
| Weston High School | Weston, Massachusetts | Maroon & Silver | public secondary | 1950 | 757 | Wildcats |