| OMNIRX 0857586 · TMA536137 | Omnicell, Inc. | 9 Electronics20 Furniture | Registered | 2000 |
| OMNIREACH 2266519 | RAKUTEN SYMPHONY SINGAPORE PTE. LTD. | 9 Electronics35 Advertising38 Telecommunications+3 | Pending | 2023 |
| OMNIRACK 2158767 · TMA1178304 | Prym Consumer USA Inc. | 20 Furniture | Registered | 2023 |
| OMNIARCH 1704486 · TMA960880 · design | Omniarch Financial Inc. | 35 Advertising36 Finance | Registered | 2017 |
| OMNIARCH 1704482 · TMA960676 | Omniarch Financial Inc. | 35 Advertising36 Finance | Registered | 2017 |
| OMNIARCH 1587011 · TMA868494 | DENTSPLY SIRONA Inc. | 10 Medical | Registered | 2014 |
| ONUREG 1767275 · TMA966383 | Celgene Corporation | 5 Pharmaceuticals | Registered | 2017 |
| OMNARIS 1436264 · TMA770181 · design | Covis Pharma GmbH | 5 Pharmaceuticals | Registered | 2010 |
| OMNARIS 1313246 · TMA748697 | Covis Pharma GmbH | 5 Pharmaceuticals | Registered | 2009 |
| ONRES 2360245 | OnRes Systems Inc. | 42 Science | Pending | 2024 |
| OneReg 2267700 | ONEREG LIMITED | 9 Electronics42 Science | Pending | 2022 |
| ONUREG 2048468 · design | Celgene Corporation | 5 Pharmaceuticals | Pending | 2020 |
| OMROWZY 2240079 · TMA1256995 | GLAXO GROUP LIMITED | 5 Pharmaceuticals | Registered | 2024 |
| Oumers 2185761 · TMA1232451 | Shenzhen Fansiyi Technology Co. Ltd. | 8 Hand | Registered | 2024 |
| ONERJI 2116595 · TMA1148250 | Mitsubishi Tanabe Pharma Corporation | 5 Pharmaceuticals | Registered | 2022 |
| ONEWORKSPACE 365 2102821 · TMA1175001 | NIRIX Inc. | 9 Electronics42 Science | Registered | 2023 |
| OWNERSBOX 2044532 · TMA1280070 | Ownersbox 3.0 Corporation | 9 Electronics25 Clothing38 Telecommunications+1 | Registered | 2025 |
| OMORC 1991107 · TMA1108149 | SHENZHEN QIAO DAKE E-COMMERCE LTD. | 9 Electronics18 Leather | Registered | 2021 |
| OMERACT 1939885 · TMA1141671 | OMERACT | 9 Electronics16 Paper35 Advertising+2 | Registered | 2022 |
| Omorc 1924303 · TMA1103525 | SHENZHEN QIAO DAKE E-COMMERCE LTD. | 7 Machines8 Hand12 Vehicles+4 | Registered | 2021 |
| OMRISNI 1923746 · TMA1112350 | an individual | 5 Pharmaceuticals | Registered | 2021 |
| OMERUS 1893323 · TMA1133717 | an individual | 6 Metal7 Machines9 Electronics+3 | Registered | 2022 |
| OMERS 1838206 · TMA1008219 · design | OMERS Administration Corporation | 9 Electronics16 Paper35 Advertising+1 | Registered | 2018 |
| OnRègle 1746882 · TMA1005681 | BidSettle Inc. | 45 Legal | Registered | 2018 |
| ONRACK 1742002 · TMA1025731 | Dell Inc. | 9 Electronics | Registered | 2019 |