In 1893 the Twenty-third Legislature took the first step toward the establishment of a teachers college at San Marcos by passing a law that the state superintendent of public instruction prescribe a course of study which teachers must complete at North Texas Normal at Denton or at Coronal Institute at San Marcos before they could be eligible to teach in the public schools of Texas. The Coronal Institute board of control did not choose to change the curriculum to conform to the new law. The Twenty-sixth Legislature, therefore, in 1899 passed an act authorizing the establishment and maintenance of a normal school at San Marcos, to be known as the Southwest Texas Normal School. The citizens of San Marcos donated eleven acres of land on an elevation known as Chautauqua Hill as the site of the college, and in 1901 the Twenty-seventh Legislature appropriated $25,000 for the erection of a building. W. D. Wood, Ed. J. L. Green, and S. V. Daniel were appointed as a local board of trustees. The school opened on September 9, 1903, with Thomas G. Harris as principal, a faculty of seventeen, and an enrollment of 303. In 1911 Harris was succeeded by Cecil E. Evans.
In 1918 the school became a full-fledged senior college, at which time the name was changed to Southwest Texas State Normal College. In 1923 the name was again changed, this time to Southwest Texas State Teachers College. In the same year the school was admitted into the American Association of Teachers Colleges. The name had been changed, but the objective of preparing teachers remained the same. In 1912 the college entered into an agreement with the San Marcos school board to use two teachers of the local school as demonstration teachers. This arrangement was discontinued in 1914, at which time the college opened its own practice school. In 1917, by local agreement, all of the East Ward School transferred to the Education Building on the campus for demonstration purposes. This arrangement lasted only one year. In 1923 negotiations for a cooperative agreement with the city schools were reopened and continued until 1933 when the arrangements were completed. By this contract the city school became the laboratory school of the college. This unusual plan, one of the few of its kind in American colleges, continued in 1950.
In 1950, under the direction of John G. Flowers who had succeeded Evans in 1942, the college had in progress an extensive expansion program, both in curriculum and in physical equipment, including six new buildings. In wartime the college made its contributions in the form of an SATC program in World War I and a CTD program in World War II. In the CTD program the college gave pre-aviation instruction to 2,200 men. In addition the college trained 1,000 men for war industries. By 1950 the campus had grown from eleven acres to sixty-five, the faculty from 17 to 105, property value from $25,000 to $3,500,000, curriculum from a limited few courses dealing largely with methods of teaching to all the subject-matter branches in which public school teachers need information—from how to teach to what to teach—and enrollment to 2,000. The school had developed from one giving instruction at the high school level to a college granting the M.A. degree with highly trained instructors in every teaching field and with a graduate school enrollment of 1,200 annually. The university experienced a tremendous growth in enrollment after 1950 to 4,461 in 1964, 6,580 in 1967, and 12,894 in the fall of 1974. The full-time teaching staff increased from 94 in 1950 to 275 in 1967 and 400 in 1971. The physical plant was greatly enlarged, with plant investment expanding to $15,418,438 in 1965. Library holdings increased from 71,650 in 1950 to 243,321 in 1969. Many curriculum changes took place, including the addition of general education requirements, new graduate programs, participation in educational television programs, enlargement of language offerings, and installation of a language laboratory. Emphasis was placed on the development of speech and hearing therapy courses and on the training of teachers for the orthopedically handicapped. Certification requirements met the standards of the Texas Education Agency.
The Fifty-sixth Texas Legislature changed the school's name to Southwest Texas State College, effective September 1, 1959, and in 1969 the legislature again authorized a name change, this time to Southwest Texas State University. During the 1960s the school gained national attention as the alma mater of the president of the United States, Lyndon Baines Johnson. James H. McCrocklin succeeded Flowers as president of the college in 1964. In 1969 McCrocklin resigned when it was revealed that much of his doctoral dissertation had been plagiarized; Leland Derrick became acting president. Billy Mac Jones was appointed president in September 1969. Jack C. Cates was named acting president in 1973, and Lee H. Smith was president from 1974 to 1981. In 1975 the Sixty-fourth Legislature established the Texas State University System. Since that time a nine-member board of regents has governed the university and the eight other schools of the state university system. Robert L. Hardesty succeeded Lee Smith as president in 1981 and was dismissed with some controversy in 1988. Michael L. Abbott served as interim president, 1988–89, and Jerome H. Supple was appointed president in 1989.
In 1979 the university purchased the former San Marcos Baptist Academy adjacent to the original campus. The Freeman Ranch, a 3,485-acre working ranch, was bequeathed to the university by Harry Freeman in 1985. A new library, constructed in the 1980s, opened in 1990 and was named in honor of Texas oilman and philanthropist Albert B. Alkek in 1991. Also housed in the university library are the Southwestern Writers Collection and the Wittliff Gallery of Southwestern and Mexican Photography. By 2009 the university library system contained over 1.4 million volumes.
In 1990 the university opened the Center for the Study of the Southwest. In 1992 some 21,302 students enrolled for the fall semester. The school had 767 full-time equivalent faculty, 1,163 staff, a budget of $144 million, and was the seventh largest public university in the state. That same year, the university purchased Fire Station Studios in downtown San Marcos to establish the Sound Recording Technology Program of the School of Music—the only degree program of its kind in the southwestern United States. In 1993 Southwest Texas State University acquired the Aquarena Springs amusement park and archeological site. In 1996 the university also offered full degree-granting graduate programs in Business Administration and Education as night classes conducted at Westwood High School in Round Rock in Williamson County. With increasing area enrollment and the gift of 101 acres for a Round Rock campus, this program evolved into construction of the Round Rock Higher Education Center which opened in 2005, and the university planned for the construction of more academic buildings on that campus.
In 1999 the university established the Institute for the History of Texas Music, which was renamed the Center for Texas Music History in 2001. The faculty numbered 1,034 in 2000. Enrollment in fall 2001 was 22,472, of whom 19,447 were undergraduates. The university was organized into schools of Applied Arts, Business, Education, Fine Arts and Communication, Health Professions, Liberal Arts, Science, and the Graduate School. With the retirement of Jerome Supple, Denise M. Trauth was appointed president in 2002. The following year the name of Southwest Texas State University was changed to Texas State University–San Marcos. Student enrollment in 2008 numbered 29,105. By 2009 the main campus consisted of 225 buildings on 457 acres, and the university owned an additional 4,777 acres. Construction projects included an upgrade of Bobcat Stadium in the effort to acquire NCAA Division 1-A status for the football program. The university offered more than 200 degree programs, including a Master of Applied Geography degree program which was the first of its kind in the nation, eight doctoral degrees, and a new nursing program to be available at the Round Rock campus in 2010. Effective September 1, 2013, the name of the university was changed to Texas State University.