| OsteoConverter 1699319 · TMA927204 | OsteoReady, LLC | 10 Medical | Registered | 2016 |
| OSTEOJECT 1833538 · TMA1033851 | Grey Wolf Animal Health Inc. | 5 Pharmaceuticals | Registered | 2019 |
| OsteoSync 2213391 · TMA1232935 | SMED-TA/TD, LLC | 10 Medical | Registered | 2024 |
| OsteoCool 1820852 · TMA1069789 | Medtronic Holding Company Sàrl | 10 Medical | Registered | 2020 |
| OSTEOCOMBO 1772447 · TMA1049348 | an individual | 5 Pharmaceuticals | Registered | 2019 |
| OSTEOSOFT 1196311 · TMA688843 | an individual | 1 Chemicals5 Pharmaceuticals | Registered | 2007 |
| OSTEOCIT 1195475 · TMA623249 | SEAFORD PHARMACEUTICALS INC. | 5 Pharmaceuticals | Registered | 2004 |
| OSTEOSENSE 1156622 · TMA602061 | Assured Natural Distribution Inc. | 5 Pharmaceuticals | Registered | 2004 |
| OSTEOSET 1012731 · TMA536283 | WRIGHT MEDICAL TECHNOLOGY, INC. | 1 Chemicals2 Paints5 Pharmaceuticals | Registered | 2000 |
| OSTEOCARE 0898436 · TMA522730 | VITABIOTICS LTD | 5 Pharmaceuticals | Registered | 2000 |
| OSTEOGON 2350698 | Owner not listed | 41 Education44 Medical | Pending | 2024 |
| OihcDosff 2250734 · TMA1276080 | Shenzhen Color Bag E-Commerce Co. Ltd | 11 Lighting | Registered | 2024 |
| OQTIQ 2249305 · TMA1268656 | Owner not listed | 9 Electronics | Registered | 2024 |
| OXDOG 2183696 · TMA1254921 | an individual | 28 Toys | Registered | 2024 |
| OctsumYing 2175194 · TMA1226166 | Guangzhou Yingbohe Trading Co. Ltd. | 21 Housewares | Registered | 2024 |
| Octocurl 2132424 · TMA1194343 | an individual | 26 Sewing | Registered | 2023 |
| Okydoky 2106201 · TMA1176625 | Zhenhui Technology (Shenzhen) Co. Ltd. | 27 Carpets | Registered | 2023 |
| OCTOGOLD 2072249 · TMA1282229 | DURADRIVE SYSTEMS INTERNATIONAL INC. | 1 Chemicals6 Metal | Registered | 2025 |
| OctaCoil 2068831 · TMA1280252 | SE Therapies Ltd. | 10 Medical | Registered | 2025 |
| OCTAS 2054480 · TMA1244891 · design | Bright International Group Holdings Ltd. | 11 Lighting35 Advertising | Registered | 2024 |
| OSTACO 2040903 · TMA1282033 | Owner not shown | 6 Metal19 Building37 Construction+2 | Registered | 2025 |
| OXDIGI 2034462 · TMA1138662 · design | Shanghai FeiTuYou Technology Co. Ltd | 9 Electronics | Registered | 2022 |
| OCTAGON 2030316 · TMA1165356 | Interprovincial Cooperative Limited | 5 Pharmaceuticals | Registered | 2023 |
| OCTECH 2021405 · TMA1263793 | Shenzhen Able Electronics Co. Ltd | 21 Housewares35 Advertising | Registered | 2024 |
| OYSTEC 2000665 · TMA1160924 | Oystec GmbH & Co. KG | 9 Electronics35 Advertising36 Finance+2 | Registered | 2023 |