The school was founded in 1930 and takes pupils from villages in the area, including Denmead, Hambledon, Purbrook & Petersfield.

After World War II, the school again included girls, though they were separated from the boys.

Now, it is a co-educational school with students of mixed ability and age range.

Cowplain School was awarded Business and Enterprise College status in September 2005.

In the 1970s, the South Wing burned down, following a fire in the Science department on the top floor.