| Ohl | Paul | Mandurah | Ford | MY ● 42 | Murray Road Board | 1922-23 |
| Ohl | Paul | Mandurah | Ford | MY ● 42 | Murray Road Board | 1923-24 |
| Ohman | A. | Queens Chambers, William Street, Perth | Buick | 1092 | Metro Private Car | 1927-28 |
| Ohyte | Q. | Cnr. Beaufort Street & Grosvernor Road, Mount Lawley | Whippet | 12858 | Metro Private Car | 1927-28 |
| Oilver | N. T. | Wellington Street | Ford Light Lorry | N 77 | Northam Municipality | 1927-28 |
| Oiney | G. H. | 187 Roberts Road, Subiaco | Buick | 1483 | Metro Private Car | 1926-27 |
| Okely | M. | North Beach | Ford Truck | P ● 2 | Perth Road Board | 1922-23 |
| Okes | F. | Gascoyne Junction | Ford Truck | GU ● 57 | Upper Gascoyne Road Board | 1926-27 |
| Okley | A. | Hector Street, Osborne Park | Chevrolet Truck | P ● 181 | Perth Road Board | 1927-28 |
| Old | C. E. | Brookton | Chevrolet | BO ● 79 | Brookton Road Board | 1925-26 |
| Old | J. | Katanning | Ford | KA ● 141 | Katanning Road Board | 1923-24 |
| Old | J. | Katanning | Ford | KA ● 141 | Katanning Road Board | 1924-25 |
| Old | J. | Katanning | Ford | KA ● 141 | Katanning Road Board | 1925-26 |
| Old | J. | Katanning | Ford | KA ● 141 | Katanning Road Board | 1926-27 |
| Old | James | Katanning | Chevrolet Truck | KA ● 141 | Katanning Road Board | 1927-28 |
| Old & Comish | - | Katanning | Maxwell | KA ● 72 | Katanning Road Board | 1917-18 |
| Old and Comish | - | Katanning | Dodge | KA 72 | Katanning Road Board | 1919 |
| Olden | A. C. W. | Labouchere Road, South Perth | Oakland | 2346 | Metro Private Car | 1927-28 |
| Olden | Mrs A | Mooliabeenee | Oakland | CH ● 8 | Chittering Road Board | 1924-25 |
| Olden | Mrs A. | MooliaBeenie | Chevrolet | CH ● 8 | Chittering Road Board | 1923 - 1924 |
| Olden | Mrs A. | Meadow Street, Guildford | Chevrolet | 2528 | Metro Private Car | 1923-24 |
| Olden | Mrs A. | Mooliabeenee | Oakland | CH ● 8 | Chittering Road Board | 1925-26 |
| Olden | Mrs A. | Mooliabeenee | Oakland | CH ● 8 | Chittering Road Board | 1926-27 |
| Oldfield | A. | Kellerberrin | Nash | KE ● 156 | Kellerberrin Road Board | 1927-28 |
| Oldfield | R. G. | Keane Street | Ford 20 H.P. | MJ 17 | Midland Junction Municipality | 1916 |
| Oldfield | R. G. | Keane Street | Ford 20 H.P. | MJ 17 | Midland Junction Municipality | 1917-18 |
| Oldfield | R. G. | Keane Street | Ford 20 H.P. | MJ 17 | Midland Junction Municipality | 1919 |
| Oldfield | R. G. | Market Street,Guildford | Buick | 1557 | Metro Private Car | 1923-24 |
| Oldfield | R. G. | Market Street, Guildford | Buick | 1557 | Metro Private Car | 1924-25 |
| Oldfield | R. G. | Market Street, Guildford | Buick | 1557 | Metro Private Car | 1925-26 |
| Oldfield | R. G. | Market Street, Guildford | Buick | 1557 | Metro Private Car | 1926-27 |
| Oldfield | R. G. Cuming | Amherst Road | Ford 20 H.P. | MJ 17 | Midland Junction Municipality | 1915 |
| Oldham | I. | Fitzgerald Street | Overland 20 H.P. | N 7 | Northam Municipality | 1916 |
| Oldham | I. R. | Fitzgerald Street | - | N 7 | Northam Municipality | 1915 |
| Oldham | Mrs J. | 3 Windsor Street, Claremont | Maxwell | 2864 | Metro Private Car | 1924-25 |
| Oldham | Mrs J. | 3 Windsor Street, Claremont | Maxwell | 2864 | Metro Private Car | 1925-26 |
| Oldham | R. O. D | - | Chevrolet | MW ● 52 | Mullewa Road Board | 1927-28 |
| Oldrim | A. | 2 Judd Street, South Perth | Rugby | 9102 | Metro Private Car | 1925-26 |
| Oldrini | A. | 12 Judd Street, South Perth | Rugby | 9102 | Metro Private Car | 1926-27 |
| Oldrini | A. | 12 Judd Street, South Perth | Rugby | 9102 | Metro Private Car | 1927-28 |
| Oleary | D. J | Walgoolan | Dodge | WT ● 13 | Westonia Road Board | 1926-27 |
| Olefent | F. V. | 17 Chester Road, Subiaco | Morris-Cowley | 9384 | Metro Private Car | 1926-27 |
| Olensloger | Miss I. C. | 1158 Hay Street, Perth | Ford | 2684 | Metro Private Car | 1924-25 |
| Olensloger | Miss I. C. | 1158 Hay Street, West Perth | Ford | 2684 | Metro Private Car | 1925-26 |
| Olensloger | Miss I. C. | 1158 Hay Street, West Perth | Ford | 2684 | Metro Private Car | 1926-27 |
| Olifent | F. V. | 17 Chester Street, Subiaco | Ford | 175 | Metro Private Car | 1922-23 |
| Olifent | F. V. | 17 Chester Street, Subiaco | Ford | 175 | Metro Private Car | 1923-24 |
| Olifent | F. V. | 17 Chester Street, Perth | Ford | 175 | Metro Private Car | 1925-26 |
| Olifent | F. V. | 17 Chester Street, Subiaco | Morris Cowley | 9384 | Metro Private Car | 1927-28 |
| Oliphant | G. | 108 Dwyer Street, Boulder | Ford | B 111 | Boulder Municipality | 1927-28 |
