The University was established by an act of the Oklahoma Territorial Legislature in 1901 as the Southwestern Normal School. The Normal School was authorized to offer two years of training and four years of preparatory work for students who were not qualified for college admission. The first classes met in 1903.
In 1920 the preparatory or academy courses were eliminated and two additional years of college work were added. The state legislature approved a change of name to Southwestern State Teachers College. The first baccalaureate degrees were awarded in May, 1921.
Other major changes in name and purposes occurred in 1939 when the institution was designated as Southwestern State College of Diversified Occupations. In 1941, it became Southwestern Institute of Technology when the college added a School of Pharmacy, degree work in the arts and sciences, and trade schools to its original function as a teacher-training institution.
The Oklahoma State Legislature in 1949 again changed the name, this time to Southwestern State College, without altering the broad scope of its purposes and education objectives. Since that time there has been full accreditation by the Higher Learning Commission (North Central Association of Colleges and Secondary Schools). In addition, the University is accredited/certified by the Accreditation Council for Pharmacy Education, Accreditation Council on Occupational Therapy Education, Accrediting Bureau of Health Education Schools, American Chemical Society, American Music Therapy Association, Association of Technology, Management and Applied Engineering, Commission on Accreditation for Health Informatics and Information Management Education, Commission on Accreditation of Physical Therapy Education, Commission on Accreditation of Athletic Training Education, Council on Social Work Education, International Assembly for Collegiate Business Education, Joint Review Committee on Education in Radiologic Technology, National Association of Schools of Music, National Council for the Accreditation of Teacher Education, National League for Nursing Accreditation Commission, Oklahoma Board of Nursing, Oklahoma Commission for Teacher Preparation, Oklahoma State Regents for Higher Education, and Technology Accreditation Commission of the Accreditation Board for Engineering and Technology.
In 1953 SWOSU inaugurated an advanced professional program leading to the Master of Teaching degree, now called the Master of Education degree. In addition to the M. Ed. degree in 16 different fields of specialization, SWOSU offers the M. S. degree in Management and School Psychology, the Master of Business Administration degree, and the Master of Music degree, and its first professional doctorate program, the Doctor of Pharmacy.
In 1974 the Oklahoma State Legislature changed the name of the institution to Southwestern Oklahoma State University. On July 1, 1987, by an act of the Oklahoma Legislature, Sayre Junior College was merged with Southwestern Oklahoma State University as a branch campus designated as Southwestern Oklahoma State University at Sayre.