| OPTAL 0427084 · TMA239473 | Henkel AG & Co. KGaA | 1 Chemicals | Registered | 1980 |
| OPHTHALAS 0566803 · TMA332343 | Alcon Inc. | 9 Electronics | Registered | 1987 |
| OPTALITY 2173028 · TMA1205448 | Digiatech, LLC | 9 Electronics35 Advertising36 Finance+2 | Registered | 2023 |
| OPTILENS 1435759 · TMA773259 | Current Lighting Solutions, LLC | 9 Electronics | Registered | 2010 |
| OPTALERT 1418090 · TMA788864 | Optalert Australia Pty Ltd. | 9 Electronics10 Medical | Registered | 2011 |
| OPTELLO 2120725 · TMA1185335 | CyberCoders, Inc. | 35 Advertising42 Science | Registered | 2023 |
| OPTEL 1836650 · TMA1002526 · design | Optel Vision Inc. | 7 Machines9 Electronics39 Transport+3 | Registered | 2018 |
| OPTEL 1791471 · TMA992516 | Optel Vision Inc. | 7 Machines9 Electronics39 Transport+3 | Registered | 2018 |
| OPTILED 1500995 · TMA869644 · design | HUIZHOU LIGHT ENGINE LTD | 9 Electronics11 Lighting | Registered | 2014 |
| OPTILL 1418165 · TMA863256 | Owner not shown | 5 Pharmaceuticals | Registered | 2013 |
| OPTILED 1377138 · TMA768354 · design | HUIZHOU LIGHT ENGINE LTD | 9 Electronics11 Lighting | Registered | 2010 |
| OPTILAC 1274470 · TMA679373 · design | CAN TECHNOLOGIES, INC. | 9 Electronics44 Medical | Registered | 2007 |
| OPTILAC 1191073 · TMA664180 | CAN TECHNOLOGIES, INC. | 9 Electronics44 Medical | Registered | 2006 |
| OPTILOC 1128712 · TMA591937 | F. VON LANGSDORFF LICENSING LIMITED | 19 Building | Registered | 2003 |
| OPTELEC 0875284 · TMA510665 | OPTELEC U.S. INC. | 9 Electronics | Registered | 1999 |
| OPTILIX 0781777 · TMA457163 | an individual | 10 Medical | Registered | 1996 |
| OPTILUX 0413978 · TMA238559 | Siemens Healthcare GmbH | 10 Medical | Registered | 1979 |
| OPTYL 0315783 · TMA167828 | Owner not shown | 6 Metal9 Electronics10 Medical+4 | Registered | 1970 |
| Optoloc 2360621 | First Light Medical Ltd | 10 Medical | Pending | 2024 |
| OPTEL 2088582 | Telecom Intellectual Property Limited | 38 Telecommunications | Pending | 2021 |
| OPTALIDON 0153828 · TMDA51835 | NOVARTIS PHARMA CANADA INC. | 5 Pharmaceuticals | Registered | 1931 |
| OPDUALAG 2235043 · TMA1244565 · design | Owner not listed | 5 Pharmaceuticals | Registered | 2024 |
| OPDUALAG 2091939 · TMA1211786 · design | BRISTOL-MYERS SQUIBB COMPANY | 5 Pharmaceuticals44 Medical | Registered | 2023 |
| OptiLake 2067132 · TMA1197556 | OASE GmbH | 1 Chemicals | Registered | 2023 |
| OBDIELA 1993514 · TMA1148757 | GENFIT | 5 Pharmaceuticals | Registered | 2022 |