| ONEPLANT 2252170 | SPARTAN CONTROLS LTD. | 9 Electronics42 Science | Pending | 2023 |
| ONEPLACE 1917019 · TMA1195057 | Trident Corporate Services (Singapore) Pte Limited as trustee for The OnePlace Unit Trust | 9 Electronics35 Advertising41 Education+1 | Registered | 2023 |
| ONEPLAN 1747101 · TMA956315 | ONEPLAN, INC. | 36 Finance39 Transport | Registered | 2016 |
| ONEBLADE 2232812 · TMA1243380 | an individual | 8 Hand | Registered | 2024 |
| ONEPULSE 2197785 · TMA1223224 | Startpulsing Limited | 35 Advertising42 Science | Registered | 2024 |
| ONEPLUS 2126442 · TMA1221249 · design | OnePlus Technology (Shenzhen) Co. Ltd. | 18 Leather25 Clothing35 Advertising+3 | Registered | 2024 |
| oneplus 1718910 · TMA946924 | OnePlus Technology (Shenzhen) Co. Ltd. | 3 Cosmetics18 Leather19 Building+3 | Registered | 2016 |
| ONEPLUS 1650101 · TMA978615 · design | OnePlus Technology (Shenzhen) Co. Ltd. | 9 Electronics | Registered | 2017 |
| OMNIPLAN 1052683 · TMA588121 | an individual | 35 Advertising36 Finance37 Construction+6 | Registered | 2003 |
| OMNIPLAST 0456929 · TMA257874 | OMNIPLAST INC. | 16 Paper20 Furniture39 Transport | Registered | 1981 |
| OneFlex 2363728 | Olympus Corporation | 10 Medical | Pending | 2024 |
| ONEPBLE 2297911 | an individual | 22 Ropes | Pending | 2023 |
| ONEPLUS 2267969 · design | Owner not listed | 9 Electronics | Pending | 2023 |
| ONFLEET 2106975 | Onfleet, Inc. | 9 Electronics42 Science | Pending | 2021 |
| ONEFLOW 2236083 · TMA1256832 | Watts Regulator Co. | 1 Chemicals11 Lighting | Registered | 2024 |
| ONEVALLEY 2143103 · TMA1185489 | OneValley, Inc. | 35 Advertising36 Finance41 Education+2 | Registered | 2023 |
| Onfleril 2141194 · TMA1193873 | MICROBIO CO. LTD. | 5 Pharmaceuticals | Registered | 2023 |
| OENOBIOL 2073693 · TMA1203832 | an individual | 3 Cosmetics5 Pharmaceuticals35 Advertising | Registered | 2023 |
| OMNIPAL 2071809 · TMA1201221 | an individual | 9 Electronics | Registered | 2023 |
| OMNYPULSE 2038265 · TMA1270723 | Biosense Webster, Inc. | 9 Electronics10 Medical | Registered | 2024 |
| OneFlock 2007254 · TMA1129134 | an individual | 45 Legal | Registered | 2022 |
| Omniflex 2004069 · TMA1129064 | Owner not shown | 17 Rubber20 Furniture | Registered | 2022 |
| OMNIBLONDE 2003410 · TMA1119639 · design | Owner not shown | 3 Cosmetics21 Housewares | Registered | 2022 |
| Omblastys 1984622 · TMA1099091 | Y-mAbs Therapeutics, Inc | 5 Pharmaceuticals42 Science | Registered | 2021 |
| OMPLIXIS 1909665 · TMA1100833 | an individual | 5 Pharmaceuticals | Registered | 2021 |