| OVERTURE 1978541 · TMA1094730 | Overture 3D Technologies, LLC | 17 Rubber | Registered | 2021 |
| OVERTURE 1760044 · TMA1020021 | Overture Donor Forum Ltd. | 42 Science | Registered | 2019 |
| OVERTURE 1592847 · TMA873215 | Novatech Canada Inc. | 19 Building | Registered | 2014 |
| OVERTURE 0811597 · TMA528695 | Opus One Winery LLC a Delaware limited liability company | 33 Wine | Registered | 2000 |
| OVERTURE 2272179 | Overture Promotions Inc. | 35 Advertising | Pending | 2023 |
| OVERTURE 2007060 | Broan-NuTone LLC, a Delaware limited liability company | 9 Electronics42 Science | Pending | 2020 |
| OVERTONES 1460795 · TMA778513 | THE FREDERICK HARRIS MUSIC CO. LIMITED | 9 Electronics16 Paper | Registered | 2010 |
| 3OVERTHREE 2230564 · design | Owner not shown | 45 Legal | Pending | 2022 |
| Overtake 2083787 · TMA1189284 | Owner not shown | 14 Jewellery16 Paper25 Clothing+3 | Registered | 2023 |
| OVERTIME 1709270 · TMA952118 | Overtime Agencies Ltd. | 37 Construction38 Telecommunications39 Transport+4 | Registered | 2016 |
| OVERTIME 2080380 | Overtime Sports, Inc. | 9 Electronics35 Advertising41 Education+1 | Pending | 2020 |
| OVEREDGER 2046783 · TMA1191476 · design | an individual | 18 Leather | Registered | 2023 |
| OVERDOSE 1937451 · TMA1159717 | an individual | 4 Oils9 Electronics34 Tobacco | Registered | 2023 |
| OVERDOSE 1598395 · TMA862885 | 9360-8065 QUÉBEC INC. | 1 Chemicals | Registered | 2013 |
| OVERDOSE 1465280 · TMA842796 | 8240531 Canada Inc. | 1 Chemicals5 Pharmaceuticals32 Beer | Registered | 2013 |
| Overtrail 2230821 | TOYOTA JIDOSHA KABUSHIKI KAISHA (also trading asTOYOTA MOTOR CORPORATION) | 12 Vehicles | Pending | 2022 |
| OPARD 2211901 · TMA1243030 | Shenzhen City LeTu Technology Co., Ltd. | 21 Housewares | Registered | 2024 |
| OPORTUN 2176718 · TMA1227121 · design | Oportun, Inc. | 36 Finance | Registered | 2024 |
| OPORTUN 2176717 · TMA1227120 | Oportun, Inc. | 36 Finance | Registered | 2024 |
| 1791 OPPORTUNE 2103329 · TMA1239430 · design | an individual | 33 Wine | Registered | 2024 |
| OPPORTUNE 1791 2099902 · TMA1239427 | an individual | 33 Wine | Registered | 2024 |
| OVERTAKE 320 2057702 · TMA1147010 | SA Designer Parfums Limited | 3 Cosmetics | Registered | 2022 |
| OPHARDT 2045329 · TMA1224912 | OP-Hygiene IP GmbH | 3 Cosmetics5 Pharmaceuticals6 Metal+7 | Registered | 2024 |
| OperationCwrl 2005421 · TMA1131075 | an individual | 24 Textiles | Registered | 2022 |
| OVERTIMEPACK 1992303 · TMA1254545 | INDUSTRIES RAD INC. | 9 Electronics12 Vehicles | Registered | 2024 |