| ONEPRO 1644588 · TMA955515 · design | MID-CONTINENTAL DENTAL SUPPLY COMPANY LTD. | 5 Pharmaceuticals | Registered | 2016 |
| ONEPROTEK 2161083 · design | an individual | 9 Electronics10 Medical | Pending | 2021 |
| OneBrock 2248946 · TMA1257067 | CTB, INC. | 35 Advertising | Registered | 2024 |
| ONEPRINT 2230900 · TMA1247194 | LEXMARK INTERNATIONAL, INC. | 2 Paints35 Advertising | Registered | 2024 |
| OMNIPROX 1726838 · TMA924226 | HONEYWELL INTERNATIONAL INC. | 9 Electronics | Registered | 2015 |
| OENOPRO 1657780 · TMA902814 | WINE CELLAR DEPOT INC. | 11 Lighting20 Furniture | Registered | 2015 |
| OMNIPRO 1527303 · TMA832068 · design | Owner not shown | 35 Advertising42 Science | Registered | 2012 |
| OMNIPRO 2356250 | MATRIX DESIGN GROUP, LLC | 9 Electronics | Pending | 2024 |
| OnePort 2281286 | FIDALIA NETWORKS INC. | 38 Telecommunications | Pending | 2023 |
| ONEBRIDGE 1433529 · TMA768330 | iAnywhere Solutions, Inc. a legal entity | 9 Electronics | Registered | 2010 |
| OneBrain 2300248 · TMA1229113 | Minnetronix Neuro, Inc. | 9 Electronics42 Science | Registered | 2024 |
| Ombriatech 2237319 · TMA1256952 | Ombriati Corp. | 9 Electronics | Registered | 2024 |
| OMBRAE 2182932 · TMA1230378 · design | Ombrae Studios Inc. | 6 Metal42 Science | Registered | 2024 |
| OMBRAE 2182931 · TMA1230377 | Ombrae Studios Inc. | 6 Metal42 Science | Registered | 2024 |
| ONEFIRE 2173679 · TMA1225306 | Guangzhou Tuoke Trading Co. Ltd. | 9 Electronics11 Lighting | Registered | 2024 |
| onebright 2170138 · TMA1221433 | ONEBRIGHT BIDCO LIMITED | 9 Electronics42 Science | Registered | 2024 |
| OMBRA 2148304 · TMA1225199 | DEL FRESCO PRODUCE LTD. | 31 Fresh | Registered | 2024 |
| Ombear 2137549 · TMA1198988 | 9447-7759 Québec inc. | 30 Coffee | Registered | 2023 |
| onebright 2125036 · TMA1216191 | ONEBRIGHT BIDCO LIMITED | 41 Education42 Science44 Medical | Registered | 2023 |
| OMNIPRESENT 2110515 · TMA1189608 · design | Omipresent Group Limited | 35 Advertising42 Science | Registered | 2023 |
| OMIBRO 2106578 · TMA1232076 · design | Zhenshi Information Technology (Shanghai) Company Limited | 9 Electronics14 Jewellery25 Clothing+2 | Registered | 2024 |
| OMBRÉCHERRY 2102246 · TMA1190598 | NATURE FRESH FARMS SALES INC. | 31 Fresh | Registered | 2023 |
| OmniBrain 2101280 · TMA1207284 | Omnirobotic Inc. | 9 Electronics | Registered | 2023 |
| OMBRE 2089590 · TMA1186073 | an individual | 26 Sewing | Registered | 2023 |
| Oumefar 2076154 · TMA1155409 | SHENZHEN CHUJIN NETWORK TECHNOLOGY CO.LTD | 7 Machines | Registered | 2022 |