The Greater Middlesex Conference (GMC) is an athletic conference comprising 35 public and private high schools located in the greater Middlesex County, New Jersey area. The league operates under the supervision of the New Jersey State Interscholastic Athletic Association. There are both competitions in Middle and High school levels.

The Conference sponsors 22 championships throughout the Fall, Winter and Spring.

The conference has a deep history in sports like basketball and baseball, with extensive records of division winners and championship tournaments (like the Middlesex County Tournament/Greater Middlesex County Tournament) highlighting dominant teams and intense rivalries.

While the specific founding year isn't always highlighted in snippets, the conference's detailed records for events like basketball (starting 1985-86) show its long-standing presence and structure. The GMC emphasizes that interscholastic athletics is a privilege, developing good citizenship and enhancing the educational experience for all student-athletes.