| Olsen | O. | Carnarvon | Overland | CN 3 | Carnarvon Municipal Council | 1924-25 |
| Olsen | O. | Carnarvon | Buick | CN 3 | Carnarvon Municipal Council | 1925-26 |
| Olsen | O. | Carnarvon | Buick | CN 3 | Carnarvon Municipal Council | 1926-27 |
| Olsen | O. | Carnarvon | Buick | CN 95 | Carnarvon Municipal Council | 1927-28 |
| Olsen | R. A. | 47, Guildford Road, Mount Lawley | Essex | 3038 | Metro Hire or Trade | 1927-28 |
| Olsen | S | Bruce Rock | Triumph Motorcycle | BK ● 10 | Bruce Rock Road Board | 1922-23 |
| Olsen | W. H. | - | Chevrolet Truck | NGN 34 | Narrogin Municipality | 1926-27 |
| Olsen | W. H. | Narrogin | G.M.C. Truck | NGN 34 | Narrogin Municipality | 1927-28 |
| Olson | A. | 69 East Street, Fremantle | Chevrolet | 12388 | Metro Private Car | 1927-28 |
| Olson | H. B. | Bateman Street, Cottesloe | Nash | 3827 | Metro Hire or Trade | 1927-28 |
| Olson | H. E. | 93 Boatty Avenue, Carlisle | Rugby | 13512 | Metro Private Car | 1926-27 |
| Olson | H. E. | 93 Beatly Avenue, Carlisle | Rugby | 13512 | Metro Private Car | 1927-28 |
| Olson | J. A. | Guildford Road, Mount Lawley | Overland 25 H.P. | P 303 | Perth Municipality | 1915 |
| Olson | J. A. | 47, Guildford Road, Mount Lawley | Overland 20 H.P. | P 303 | Perth Municipality | 1917-18 |
| Olson | J. A. | 47 Guildford Road, Mount Lawley | Overland 20 H.P. | P 303 | Perth Municipality | 1919 |
| Olson | John A. | 47 Guildford Road, Mount Lawley | Overland 20 H.P. | P 303 | Perth Municipality | 1916 |
| Olson | W. J. | Laverton | Ford Truck | MG ● 13 | Mount Margaret Road Board | 1925-26 |
| Olson | W. J. | Laverton | Ford Truck | MG ● 15 | Mount Margaret Road Board | 1926-27 |
| Olson | W. J. | Laverton | Ford Truck | MG ● 20 | Mount Margaret Road Board | 1927-28 |
| Oma | A. W. | Woodbridge Terrace | Douglas 3½ H.P. Motorcycle | MJ 19 | Midland Junction Municipality | 1919 |
| Oma | A. W. | Woodbridge Terrace | Indian 7-9 H.P. | MJ 23 | Midland Junction Municipality | 1919 |
| Oma | A. W. | 141 Railway Parade, Subiaco | Ford | 7452 | Metro Private Car | 1925-26 |
| Oma | A. W. | 177 Rokeby Road, Subiaco | Ford | 7452 | Metro Private Car | 1926-27 |
| Oma | Arthur W. | 84 Broome Street, Perth | Harley Davidson | 1126 | Metro Motorcycle | 1922-23 |
| Oma | H. W. | Kalamunda | Lacre Wagon | DR ● 35 | Darling Range Road Board | 1924-25 |
| Oma | L. E. | 36 Byars Road, West Midland | Chevrolet | 4602 | Metro Private Car | 1925-26 |
| Oma | Mrs L. E | 24 Wittenoom Street, East Perth | Chevrolet | 4602 | Metro Private Car | 1927-28 |
| Oma | Mrs L. E. | 24 Wittenoom Street, East Perth | Chevrolet | 4602 | Metro Private Car | 1926-27 |
| Oma | Mrs R. A. | 36 Byars Road, West Midland | Chevrolet | 4602 | Metro Private Car | 1924-25 |
| Oma | Mrs V. A. | 177 Railway Road, Subiaco | Fiat | 9461 | Metro Private Car | 1927-28 |
| Oma | V. C. | 308 Onslow Road, Subiaco | Ford Wagon | 12937 | Metro Private Car | 1927-28 |
| Omadie | P. | Toodyay | Chevrolet Truck | T ● 78 | Toodyay Road Board | 1927-28 |
| Omadie | Peter | Toodyay | Reo Truck | T ● 65 | Toodyay Road Board | 1927-28 |
| Omar | H. W. | 19 Woodbridge Terrace, Midland | Napier | 3152 | Metro Private Car | 1922-23 |
| Omar | H. W. | 19 Woodbridge Terrace, Maylands | Napier | 3152 | Metropolitan Hire and Trade Cars | 1923-24 |
| Omer | H. W. | Midland Junction | Lacre truck | DR ● 33 | Darling Range Road Board | 1923-24 |
| Omer | H. W. | Midland Junction | Centenell | DR ● 35 | Darling Range Road Board | 1923-24 |
| Omeroed | A. | Fitzgerald Street | B.S.A. 3½ H.P. Motorcycle | N 13 | Northam Municipality | 1916 |
| Omodei | J. J. | Hay Street | Ford Truck | KMC 171 | Kalgoorlie Municipality | 1924-25 |
| Omodel | G. | Osborne Park Hotel, Osborne Park | Dodge | 1685 | Metro Private Car | 1927-28 |
| Omodel | J. | 227 Hay Street | Ford Truck | KMC 171 | Kalgoorlie Municipal Council | 1925-26 |
| Omodie | P. | Toodyay | Chevrolet Truck | T ● 78 | Toodyay Road Board | 1926-27 |
| ONeill | D. I. | Tambellup | Ford | TA ● 38 | Tambellup Road Board | 1927-28 |
| Onions | B. L. | Busselton | Hupmobile | BN 45 | Municipality of Busselton | 1925-26 |
| Onions | B. L. | Busselton | Hupmobile | BN 45 | Municipality of Busselton | 1926-27 |
| Onions | B. L. | Busselton | Hupmobile | BN 45 | Municipality of Busselton | 1927-28 |
| Onions | E. E. | East Street | Douglas 2¾ H.P. Motorcycle | F 94 | Fremantle Municipal Council | 1919 |
| Onions | E. E. | Cnr. East & Forrest streets, East Fremantle | Chev. | 869 | Metro Private Car | 1924-25 |
| Onions | E. E. | East & Forrest streets, East Fremantle | Chevrolet | 869 | Metro Private Car | 1925-26 |
| Onions | E. E. | Forrest Street, Fremantle | Essex | 12535 | Metro Private Car | 1927-28 |
