| OMOZEN 2050879 · TMA1167986 · design | an individual | 21 Housewares | Registered | 2023 |
| OMAZEN 1563824 · TMA863747 | PIVOTAL THERAPEUTICS INC. | 5 Pharmaceuticals | Registered | 2013 |
| OMAJIN 2311813 | Owner not shown | 9 Electronics10 Medical11 Lighting+1 | Pending | 2024 |
| OMCAN 1901457 · TMA1093961 | OMCAN MFG. & DISTRIBUTING CO. INC. | 7 Machines8 Hand11 Lighting+3 | Registered | 2021 |
| OMNIGEN 1948188 · TMA1281621 | Prince Agri Products, Inc. | 1 Chemicals5 Pharmaceuticals | Registered | 2025 |
| OMEZONE 1456223 · TMA790144 | AKM Services International Limited | 5 Pharmaceuticals | Registered | 2011 |
| OMNIKIN 0647043 · TMA390145 | OMNIKIN INC. | 6 Metal9 Electronics12 Vehicles+9 | Registered | 1991 |
| OMNISAN 2194122 · design | OmniLyte Enviro Inc. | 1 Chemicals3 Cosmetics5 Pharmaceuticals+2 | Pending | 2022 |
| OMNISAN 2113493 | OmniLyte Enviro Inc. | 1 Chemicals5 Pharmaceuticals11 Lighting+3 | Pending | 2021 |
| OMEGAMAZING 2212477 · TMA1243116 | Vibrant Health Products Inc. dba Silver Hills Bakery | 30 Coffee35 Advertising43 Restaurants | Registered | 2024 |
| Omzanclo 2188197 · TMA1282711 | CELLTRION, INC. | 5 Pharmaceuticals | Registered | 2025 |
| ONSEMI 2163807 · TMA1197147 · design | SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC | 9 Electronics40 Treatment42 Science | Registered | 2023 |
| ONSEMI 2162326 · TMA1196045 | SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC | 9 Electronics40 Treatment42 Science | Registered | 2023 |
| OMNISMART 2146610 · TMA1187769 | HONEYWELL INTERNATIONAL INC. | 9 Electronics | Registered | 2023 |
| OMEGANOMIX 2142609 · TMA1200382 | an individual | 20 Furniture | Registered | 2023 |
| OMEGANOMIC 2142608 · TMA1200381 | an individual | 20 Furniture | Registered | 2023 |
| ONEAGENT 2141675 · TMA1250808 | Dynatrace LLC | 9 Electronics | Registered | 2024 |
| OneCem 2134167 · TMA1240962 | Holcim Technology Ltd | 19 Building | Registered | 2024 |
| OWANQIANG 2131450 · TMA1194321 | Shenzhen Heliliang Electronic Commerce Co. Ltd. | 11 Lighting | Registered | 2023 |
| ONSUMCO 2116225 · TMA1183023 | an individual | 5 Pharmaceuticals | Registered | 2023 |
| OMWEEKEND 2101656 · TMA1155469 · design | FOKDA POPO PTE LTD | 35 Advertising | Registered | 2022 |
| ONSON 2032896 · TMA1139663 | Shenzhen Weizhisheng E-Commerce Co.Ltd. | 7 Machines | Registered | 2022 |
| ONESING 2020998 · TMA1157956 | Shenzhen Suruiketa Technology Co. Ltd | 25 Clothing | Registered | 2022 |
| ONSON 2003667 · TMA1143464 · design | Shenzhen Weizhisheng E-Commerce Co.Ltd. | 7 Machines | Registered | 2022 |
| ONCOONE 2003628 · TMA1127198 | OncoOne Research & Development GmbH | 5 Pharmaceuticals42 Science44 Medical | Registered | 2022 |