| OAKLANDS 1638279 · TMA909722 | an individual | 20 Furniture35 Advertising | Registered | 2015 |
| OAKLANDS 1230594 · TMA645234 | LIDL STIFTUNG & CO. KG | 31 Fresh | Registered | 2005 |
| OAKLAND 1762392 · TMA1011741 | Green Brand LLC | 30 Coffee | Registered | 2018 |
| OAKLAND 1698624 · TMA973403 | DUCHESNE ET FILS LTEE | 19 Building | Registered | 2017 |
| OAKLAND 1576904 · TMA860486 | 0898852 B.C. Unlimited Liability Company dba D'ADDARIO, a legal entity | 9 Electronics15 Musical | Registered | 2013 |
| OAKLAND 0991617 · NFLD1617 · design | General Motors LLC | 12 Vehicles | Registered | 1928 |
| OAKLAND 0991224 · NFLD1224 · design | OAKLAND MOTOR CAR COMPANY (A MICHIGAN CORPORATION) | 12 Vehicles | Registered | 1924 |
| OAKLAND 0738258 · TMA441452 | Bootlegger Clothing Inc. | 14 Jewellery18 Leather25 Clothing+1 | Registered | 1995 |
| Oaklynn 2304425 | CANADA XUAN DA ANTIQUE ART PRODUCTS INTERNATIONAL TRADE CO. LTD. | 2 Paints3 Cosmetics5 Pharmaceuticals+14 | Pending | 2024 |
| OXYLINE 2037484 · TMA1155073 · design | Owner not shown | 9 Electronics | Registered | 2022 |
| OZOLINE 1968891 · TMA1255580 | Messer Canada Inc. | 1 Chemicals | Registered | 2024 |
| Ozalin 1897228 · TMA1091900 | an individual | 5 Pharmaceuticals | Registered | 2021 |
| OKLand 1894272 · TMA1073671 | AUCKLAND MEDICAL POLYMER (TIANJIN) CO. LTD. | 5 Pharmaceuticals10 Medical20 Furniture+1 | Registered | 2020 |
| OKALIN 1732334 · TMA946872 · design | GUANGZHOU WILKEN SPORTS CO. LTD. | 18 Leather25 Clothing28 Toys | Registered | 2016 |
| OcuLine 1683977 · TMA908886 | CanMedApps, Inc | 9 Electronics35 Advertising44 Medical | Registered | 2015 |
| OXOLIN 1462224 · TMA787503 | LINPAC Packaging Limited | 16 Paper17 Rubber | Registered | 2011 |
| OXILINE 1178337 · TMA636305 | RESCO PRODUCTS, INC. | 19 Building | Registered | 2005 |
| OXILINE 2372143 | an individual | 6 Metal7 Machines9 Electronics+2 | Pending | 2024 |
| OSLINE 2312678 | an individual | 28 Toys | Pending | 2024 |
| OSHLINE 0911252 | The Canadian Centre for Occupational Health and Safety | 1 Chemicals2 Paints3 Cosmetics+42 | Pending | 1999 |
| OCULAN 2241542 · TMA1257037 | STRYKER CORPORATION | 10 Medical | Registered | 2024 |
| OZYILIAN 2228499 · TMA1252774 | Dongguan Binhe Clothing Co. Ltd. | 25 Clothing | Registered | 2024 |
| OSLANE 2202888 · TMA1238906 · design | an individual | 6 Metal28 Toys | Registered | 2024 |
| OXILAM 2141935 · TMA1200330 | Shenzhen Axi Technology Co. Ltd. | 11 Lighting | Registered | 2023 |
| OSELAN 2136792 · TMA1238162 | SETALG | 1 Chemicals | Registered | 2024 |