| ODOURACT 1571407 · TMA856557 | Gesco Limited Partnership | 1 Chemicals27 Carpets | Registered | 2013 |
| OTTERSPACE 2215744 · TMA1233988 | OTTERSPACE | 20 Furniture24 Textiles | Registered | 2024 |
| OTRUSVYQUE 2193069 · TMA1218733 | GLAXO GROUP LIMITED | 5 Pharmaceuticals | Registered | 2024 |
| ODORCAPTURE 360 2173051 · TMA1275801 | Spectrum Brands Pet LLC | 5 Pharmaceuticals31 Fresh | Registered | 2024 |
| OTHERSKIN 2159877 · TMA1275734 | FDG Entertainment GmbH & Co. KG | 9 Electronics16 Paper25 Clothing+3 | Registered | 2024 |
| OTTERGRIP 2150836 · TMA1268301 | Otter Products LLC | 9 Electronics | Registered | 2024 |
| OUTDOORSMAN 2141843 · TMA1193874 | Bushnell Inc. | 9 Electronics | Registered | 2023 |
| ODORSHEER 2100567 · TMA1173826 · design | KADENA INDUSTRIES LIMITED | 25 Clothing | Registered | 2023 |
| OUTREACH 2064937 · TMA1192501 | OUTREACH CORPORATION | 9 Electronics35 Advertising42 Science | Registered | 2023 |
| OTraki 2062398 · TMA1172138 | Shenzhen Qiyu Technology Co. Ltd. | 24 Textiles | Registered | 2023 |
| Odorwise 2035357 · TMA1138669 | Envirowise Solutions Inc. | 1 Chemicals5 Pharmaceuticals | Registered | 2022 |
| OTTERSPOT 2010556 · TMA1108348 | Otter Products LLC | 9 Electronics | Registered | 2021 |
| OTRS 1918248 · TMA1121861 · design | Broadleaf Co. Ltd. | 9 Electronics42 Science | Registered | 2022 |
| OUTRIGGER 1877370 · TMA1050466 | DITU INC. | 28 Toys | Registered | 2019 |
| ODORGRAB 1875158 · TMA1049523 | Helen of Troy Limited | 11 Lighting | Registered | 2019 |
| OUTRIGGER 1870672 · TMA1085564 | Blacksmith OTR, LLC | 12 Vehicles | Registered | 2020 |
| ODORCLEAR 1817695 · TMA1064986 · design | The Procter & Gamble Company | 4 Oils | Registered | 2019 |
| OUTDOORACTIVE 1784382 · TMA1026305 · design | an individual | 9 Electronics16 Paper35 Advertising+4 | Registered | 2019 |
| OUTREACH 1751920 · TMA1011180 | OUTREACH CORPORATION | 35 Advertising42 Science | Registered | 2018 |
| OUTERKNOWN 1681045 · TMA1058756 | Outerknown, LLC | 25 Clothing | Registered | 2019 |
| OUTERKNOWN 1681043 · TMA1058757 · design | Outerknown, LLC | 25 Clothing | Registered | 2019 |
| OUTERKNOWN 1681040 · TMA1058767 · design | Outerknown, LLC | 9 Electronics14 Jewellery16 Paper+2 | Registered | 2019 |
| OUTERKNOWN 1681029 · TMA1058755 | Outerknown, LLC | 9 Electronics14 Jewellery16 Paper+2 | Registered | 2019 |
| ODORACTION 1631759 · TMA935764 | IS CANADA INC. | 5 Pharmaceuticals35 Advertising | Registered | 2016 |
| OUTDOORSMART!! 1607700 · TMA999890 | OUTDOORsmart! Inc. | 9 Electronics16 Paper | Registered | 2018 |