The Mississippi Valley Triangular League is a former high school athletic conference in Wisconsin. Comprising three schools in west central Wisconsin, it was in existence from 1936 to 1940 and its member schools were affiliated with the Wisconsin Interscholastic Athletic Association.
The Mississippi Valley Triangular League was formed as a basketball-only conference in 1936 by three schools that left the Little Eight Conference in 1935: Augusta, Black River Falls and Neillsville. Competition lasted for four years before the conference stopped keeping records in 1940, however the conference members continued to schedule each other on an annual basis until the late 1950s.