| Onslow | A. C. | Attorney General | Perth | 1881 | WA Almanack |
| Onslow | A. C. | Attorney General | Perth | 1882 | WA Almanack |
| Onslow | A. C. | Chief Justice | Perth | 1884 | WA Almanack |
| Onslow | A.C. | Chief Justice | Perth | 1884 | Herald Almanack |
| Onslow | His Honor A. C. | Chief Justice | Perth | 1887 | WA Almanack |
| Onslow | His Honor A. C. | Chief Justice | Perth | 1888 | WA Almanack |
| Onslow | His Honour A. C. | Chief Justice | Perth | 1889 | WA Almanack |
| Onslow | Hon. A C. | Chief Justice | Perth | 1886 | WA Almanack |
| Onslow | Hon. A. C. | Chief Justice | Perth | 1885 | Herald Almanack |
| Onslow | Sir A. | Chief Justice | Saint George's Terrace, Perth | 1897 | Witton's Directory |
| OOonnor | J. | Tidewaiter | Fremantle | 1877 | WA Almanack |
| Ooran | J. von | Gardener | Guildford | 1897 | Witton's Directory |
| Oram | N. R. | Sec, Coolgardie Club | Sylvester Street, Coolgardie | 1897 | Witton's Directory |
| Orchard | W. | Clerk | Peak Hill | 1897 | Witton's Directory |
| Ord | B. D. | Clerk Governers Office | Perth | 1888 | WA Almanack |
| Ord | B. D. | Clerk Governors Office | Perth | 1889 | WA Almanack |
| Ord | H. St. G. | Private Secretary | Perth | 1879 | Herald Almanack |
| Ord | H. St. G. | Private Secretary | Perth | 1880 | Herald Almanack |
| Ord | Lieut. St. J. St. G. | Private Sec. to H.E. the Governor | Perth | 1879 | WA Almanack |
| Ord Lieut. | St. J. St. G. | Privite Sectry to H. E. the Governor | Perth | 1880 | WA Almanack |
| OReefe | D. | Overseer P. & O. Co.s Coal Wharf | Albany | 1875 | WA Almanack |
| OReilly | P. | Pensioner | Bunbury | 1877 | WA Almanack |
| OReilly | P. | Pensioner and Farmer | Wellington District (Bunbury, Etc) | 1880 | WA Almanack |
| OReilly | P. | Pensioner | Wellington District (Bunbury, Etc.) | 1881 | WA Almanack |
| OReilly | Rev. J. | Roman Catholic Chaplain | Perth | 1872 | WA Almanack |
| OReilly | Rev. J. | R.C. Chaplain | Fremantle | 1877 | WA Almanack |
| OReily | Rev J. | Roman Catholic Chaplain | Fremantle | 1880 | WA Almanack |
| OReily | Rev. J. | Roman Catholic Chaplain | Fremantle | 1874 | WA Almanack |
| OReily | Rev. J. | R.C. Chapln. | Fremantle | 1875 | WA Almanack |
| OReily | Rev. J. | Roman Catholic Chaplain | Fremantle | 1882 | WA Almanack |
| OReily | Rev. J. | R.C. Chaplain | Fremantle | 1884 | WA Almanack |
| OReily | Rev. John | Roman Catholic Chaplain | Newcastle | 1873 | WA Almanack |
| OReily | Rev.J. | R.C.Chaplain | Fremantle | 1881 | WA Almanack |
| Orieal | Peter | Bootmaker | Victoria District (Geraldton) | 1879 | WA Almanack |
| Oriel | D. | - | Perth | 1887 | WA Almanack |
| Oriel | D. | Cabinet Maker | Perth | 1888 | WA Almanack |
| Oriel | D. | Cabinet Maker | Perth | 1889 | WA Almanack |
| Oriel | I. | Houseowner | Perth | 1884 | Herald Almanack |
| Oriel | J. | House Proprietor | Perth | 1884 | WA Almanack |
| Oriel | L. | Houseowner | Perth | 1883 | Herald Almanack |
| Oriel | L. | Houseowner | Perth | 1885 | Herald Almanack |
| Oriel | L. | House Owner | Perth | 1886 | WA Almanack |
| Oriel | L. | Houseowner | Perth | 1887 | WA Almanack |
| Oriel | L. | Houseowner | Perth | 1888 | WA Almanack |
| Oriel | L. | Houseowner | Perth | 1889 | WA Almanack |
| Oriel | Y. | Houseowner | Perth | 1882 | Herald Almanack |
| Orielly | G. | Boarding House | 72 Goderich Street, Perth | 1897 | Witton's Directory |
| Orielly | S. | | By-Sea Road, Fremantle | 1897 | Witton's Directory |
| Oriental Hairdressing Saloon | Stuart, J. | | Hutt Street, Perth | 1897 | Witton's Directory |
| Oril | Y. | | 20 Goderich Street, Perth | 1897 | Witton's Directory |