| OdySight 1886892 · TMA1082789 | Owner not shown | 9 Electronics35 Advertising38 Telecommunications+3 | Registered | 2020 |
| ODYSIGHT 2285314 | ODYSIGHT.AI LTD | 9 Electronics10 Medical42 Science | Pending | 2023 |
| Odseciran 2354109 | Ezhou Hemu Trading Co. Ltd. | 5 Pharmaceuticals16 Paper | Pending | 2024 |
| OdysseyGO 2219084 · TMA1246909 | GRTHealth Inc. | 9 Electronics38 Telecommunications42 Science+1 | Registered | 2024 |
| OTTSIGNATURE 2176766 · TMA1227141 | OTTSIGNATURE INC | 7 Machines11 Lighting35 Advertising | Registered | 2024 |
| OUTKAST 2165484 · TMA1266851 | High Schoolers, LLC | 9 Electronics25 Clothing41 Education | Registered | 2024 |
| Oatdacious 2115492 · TMA1221220 | Watermark Naturals Inc. | 5 Pharmaceuticals | Registered | 2024 |
| OTSUKARESAMA 2058241 · TMA1172048 | Godspeed Brewery Inc. | 32 Beer35 Advertising | Registered | 2023 |
| OUTSYSTEMS 2046742 · TMA1108838 | Owner not shown | 9 Electronics42 Science | Registered | 2021 |
| OUTGEEK 2018697 · TMA1157064 · design | Shenzhen Jingcheng Huachuang Technology Co.ltd | 28 Toys | Registered | 2022 |
| OUTGEEK 2018696 · TMA1160967 · design | Shenzhen Jingcheng Huachuang Technology Co.ltd | 8 Hand | Registered | 2023 |
| OUTSIZE 2018362 · TMA1119678 | Dyson Technology Limited | 7 Machines | Registered | 2022 |
| OUTCAST 2015768 · TMA1132147 | Chauvet & Sons, LLC | 11 Lighting | Registered | 2022 |
| OUTCAST 2003263 · TMA1201027 · design | Outcast Foods Inc. A Nova Scotia corporation | 40 Treatment | Registered | 2023 |
| OUTCAST 2003262 · TMA1202288 | Outcast Foods Inc. A Nova Scotia corporation | 40 Treatment | Registered | 2023 |
| ODYSSEUS 1947934 · TMA1220075 | LANGE UHREN GMBH | 14 Jewellery | Registered | 2024 |
| ODACYUS 1759587 · TMA1059544 | Paratek Pharmaceuticals, Inc. | 5 Pharmaceuticals | Registered | 2019 |
| OTSUKA 1759402 · TMA1037531 · design | Otsuka Holdings Co. Ltd. | 1 Chemicals30 Coffee | Registered | 2019 |
| OTSUKA 1751819 · TMA1036901 · design | Otsuka Holdings Co. Ltd. | 9 Electronics | Registered | 2019 |
| OUTSHOCK 1750713 · TMA981852 | Owner not shown | 9 Electronics18 Leather25 Clothing+1 | Registered | 2017 |
| OTESUS 1640407 · TMA917333 | Maquet GmbH | 10 Medical37 Construction40 Treatment | Registered | 2015 |
| OTXGIS 1509632 · TMA822830 | OTX Systems Ltd. | 42 Science | Registered | 2012 |
| OTSUKA 1504136 · TMA833207 · design | Otsuka Holdings Co. Ltd. | 5 Pharmaceuticals10 Medical29 Meat+2 | Registered | 2012 |
| ODYSSEUS 1502469 · TMA863321 | SANOFI | 42 Science | Registered | 2013 |
| OUTCHOC 1441489 · TMA782336 | an individual | 9 Electronics17 Rubber18 Leather+6 | Registered | 2010 |