Oklahoma State University–Stillwater, located in Stillwater, Oklahoma, is an institution of higher learning founded in 1890 as a land-grant university under the Morrill Act. Originally known as Oklahoma Agricultural and Mechanical College (Oklahoma A&M), it is the flagship institution of the Oklahoma State University System. The campus had a total enrollment of 20,834 students for the 2005-06 academic year, 18,909 of which were undergraduates.

History
On December 24, 1890, the Oklahoma Territorial Legislature finally gained approval for Oklahoma Territorial Agricultural and Mechanical College, the land-grant university established under the Morrill Act of 1862. It specified that the college was to be within Payne County. Such an ambiguous description created rivalry between towns within the county, with Stillwater ultimately winning out. Upon statehood in 1907, "Territorial" was dropped from its title.

The first students assembled for class on December 14, 1891. Classes were held for two and one-half years in local churches until the first academic building, later known as Old Central, was dedicated on June 15, 1894, on the southeast corner of campus. In 1896, Oklahoma A&M held its first commencement with six male graduates.

Much of the growth of OAMC can be attributed to work of Henry G. Bennett, who served as the school's president from 1928 to 1950. Early in his tenure Dr. Bennett developed a strategic vision for the physical expansion of the university campus. His vision was followed for more than fifty years and made the university what it is today, including the Georgian architecture that permeates the campus. The focal point of his vision was a new library, which became a reality when the Edmon Low Library opened in 1953.

On May 15, 1957, Oklahoma A&M changed its name for the final time to Oklahoma State University to reflect the broadening scope of curriculum offered. Branches have since been added in Okmulgee, Oklahoma City, and Tulsa to the Oklahoma State University System, with the Stillwater campus as the flagship institution.

In 2005, OSU announced its "Campus Master Plan", an ambitious campaign to enhance academic, athletic, and administrative facilities. It is intended to be an extension of the Bennett Plan developed almost 80 years ago. Over $800 million is planned to be spent on construction and renovation to be completed over twenty years.

The Plan calls for an "athletic village" where all of the university's athletic facilities will be located on the main campus. To accomplish this goal, the athletic department has bought all (or nearly all) the property north of Boone Pickens Stadium up to McElroy between Knoblock and Washington streets. This has drawn criticism from the city of Stillwater and those property owners. While the vast majority of the real estate was rental property targeting college students, a few owners were longtime residents. OSU responded by offering property owners well above their appraised value. At present, there is a lone holdout in this parcel of land, who has sued OSU over their right to use eminent domain. Plans include the construction of an indoor practice facility for most sports, a soccer stadium/outdoor track, a tennis complex, and a baseball stadium.