SWOSU was first established through an act of the Oklahoma Territorial Legislature in 1901 as "Southwestern Normal School", although no classes were held until 1903.

In 1920, the preparatory part of the school closed and a four-year baccalaureate degree program replaced it.

The first bachelor's degrees by the renamed "Southwestern State Teachers College" were awarded in the spring of 1921.

The Great Depression brought several attempts to close the school for financial reasons.

The first graduate degree, a Masters of Teaching, was added in 1953, and the school was officially designated as "Southwestern Oklahoma State University" in 1974.

The campus is the grounds for several diverse buildings, some dating back to the school's opening in 1903, and some as recent as 2014.

The university competes at the NCAA Division II level as a member of the Great American Conference (GAC).