| OPTREX 1790747 · TMA1045313 | OPTREX LIMITED | 3 Cosmetics5 Pharmaceuticals10 Medical | Registered | 2019 |
| OPTREX 1766217 · TMA979830 · design | OPTREX LIMITED | 3 Cosmetics5 Pharmaceuticals | Registered | 2017 |
| OPTREX 0172297 · UCA9890 | OPTREX LIMITED | 3 Cosmetics | Registered | 1937 |
| OPETRIA 2009926 · TMA1260714 | Wakamoto Pharmaceutical Co. Ltd. | 5 Pharmaceuticals | Registered | 2024 |
| OPTRA 1273477 · TMA675096 | IVOCLAR VIVADENT, INC. | 5 Pharmaceuticals10 Medical | Registered | 2006 |
| OBTRYX 1232631 · TMA691648 | Boston Scientific Limited | 10 Medical | Registered | 2007 |
| OPTREL 1075205 · TMA574333 | an individual | 9 Electronics10 Medical11 Lighting+4 | Registered | 2003 |
| OPTRAK 1050578 · TMA571828 | Optrak Distribution Software Ltd. a corporation of Britain | 9 Electronics35 Advertising42 Science | Registered | 2002 |
| OPTRA 0787185 · TMA469654 | LEXMARK INTERNATIONAL, INC. | 9 Electronics | Registered | 1997 |
| OPTRA 2197631 | LEXMARK INTERNATIONAL, INC. | 9 Electronics35 Advertising42 Science | Pending | 2022 |
| OPTRIENT 2229030 · TMA1252871 | Koch Agronomic Services, LLC | 1 Chemicals | Registered | 2024 |
| OPTERION 2075846 · TMA1168456 | an individual | 5 Pharmaceuticals10 Medical42 Science | Registered | 2023 |
| OPTRELL 2051449 · TMA1228572 | Biosense Webster, Inc. | 10 Medical | Registered | 2024 |
| OPTIRUN 1841136 · TMA1057462 | an individual | 9 Electronics41 Education42 Science | Registered | 2019 |
| OPTRUST 1733115 · TMA941697 · design | an individual | 9 Electronics16 Paper35 Advertising+1 | Registered | 2016 |
| OPTRUST 1733114 · TMA942851 | an individual | 9 Electronics16 Paper35 Advertising+1 | Registered | 2016 |
| OPTAROS 1418822 · TMA813523 | Optaros, Inc. | 42 Science | Registered | 2011 |
| OPTREOZ 1398895 · TMA829242 | 3M Company | 10 Medical | Registered | 2012 |
| OPTIAIR 1378509 · TMA786773 | Cummins Filtration Inc. | 7 Machines | Registered | 2011 |
| OPTREVE 1294328 · TMA697165 | Screenlife, LLC | 42 Science | Registered | 2007 |
| OPTIRAY 0603262 · TMA355152 | Liebel-Flarsheim Company LLC | 5 Pharmaceuticals | Registered | 1989 |
| OPTERAN 2139685 | Opteran Technologies Limited | 9 Electronics35 Advertising42 Science | Pending | 2021 |
| OPTIRINSE 2184544 · TMA1230591 | Kobayashi Pharmaceutical Co. Ltd. | 5 Pharmaceuticals10 Medical | Registered | 2024 |
| OPTRAFFIC 2048599 · TMA1146982 | OPTRAFFIC CO. LTD. | 9 Electronics | Registered | 2022 |
| OPHYTRIUM 1931651 · TMA1155623 | an individual | 1 Chemicals | Registered | 2022 |