Browse Organisations - O
- Oenpelli Mission (1925 - 1975)
- Office of the Administrator, Northern Territory [I] (1911 - 1927), Australian Government
- Office of the Administrator, Northern Territory [II] (1931 - 1978), Australian Government
- Office of the Administrator, Northern Territory [II] (1978 - ), Northern Territory of Australia
- Office of the Government Resident, Central Australia (1927 - 1931), Australian Government
- Office of the Government Resident, North Australia (1927 - 1931), Australian Government
- Office of the Minister Controlling the Northern Territory (1892 - 1909), South Australian Government
- Office of the Minister for the Northern Territory (1909 - 1911), South Australian Government
- Office of the Minister of Education and of the Northern Territory (1889 - 1892), South Australian Government
- Old Alice Springs Gaol
- see Her Majesty's Gaol and Labour Prison, Alice Springs (1938 - 1996)
- The Old Gaol
- see Stuart Town Gaol (1909 - 1933)
- Old Uniya
- see Queen of the Holy Rosary Mission (1886 - 1891)
- Our Lady of the Sacred Heart Primary School (1938 - 1983?)
- Our Lady of Victories Mission
- see Garden Point Mission (1941 - 1969)