| Label | Dates | |
|---|---|---|
| Opening Doors TCU Student Chapter | 2022-2024 | View Item |
| Opera Organization for Students | 2024- | View Item |
| Opera Studio | 2003- | View Item |
| Opera Theatre | 1971-2003 | View Item |
| Oracle | 2003-2005 | View Item |
| Oratorical Association | 1902-1936 | View Item |
| Order of Omega | 1975- | View Item |
| Order of the Rainbow for Girls | 1928-1929 | View Item |
| Organization for Supply Chain Studies | 2004-2024 | View Item |
| Organization of Latin American Students | 1988-2006 | View Item |
| Orientation | 1946- | View Item |
| Orientation Student Advisors | 1990-1996 | View Item |
| Orientation Student Assistants | 1996-2014 | View Item |
| Orienteering Club | 1977-1979 | View Item |
| Orpheus Club | 1903-1904 | View Item |
| Orthodox Christian Campus Ministries | 2024- | View Item |
| Orthodox Christian Fellowship | 2021- | View Item |
| Outcasts | 1929-1935 | View Item |
| Outdoor Programs | 2003- | View Item |
| Outdoor Recreation Club | 1968-1971 | View Item |
| Overdose Awareness | 2023- | View Item |
| P.A.L.S. | 1917-1918 | View Item |
| P.I.G. Club | 1912-1914 | View Item |
| P.N.S. Club | 1911-1912 | View Item |
| P.O.B. | 1910 | View Item |