| OKLAHOMA DIET SERVICES, INC. | — | 1900361608 | 1981-01-21 | Inactive | |
| OKLAHOMA DISPOSAL SYSTEMS, INC. | — | 1900377736 | 1981-11-18 | Inactive | |
| OKLAHOMA E. T. CLINIC, INC. | — | 2200365144 | 1981-03-26 | Inactive | |
| OKLAHOMA EAGLE RESEARCH FOUNDATION, INC. | — | 2100370259 | 1981-06-29 | Active | |
| OKLAHOMA ELECTRIC RIG SERVICE, INC. | — | 1900363599 | 1981-02-27 | Inactive | |
| OKLAHOMA EMERGENCY ROOM AND MEDICAL SERVICES, INC. | — | 1900371852 | 1981-07-29 | Inactive | |
| OKLAHOMA ENERGIES DRILLING CORPORATION | — | 1900369964 | 1981-06-24 | Inactive | |
| OKLAHOMA ENERGY CORPORATION | — | 1900373880 | 1981-09-04 | Inactive | |
| OKLAHOMA ENERGY EQUIPMENT CORPORATION | — | 1900374735 | 1981-09-22 | Inactive | |
| OKLAHOMA ENERGY MANAGEMENT, INC. | — | 1900365885 | 1981-04-09 | Inactive | |
| OKLAHOMA EQUIPMENT COMPANY, INCORPORATED | — | 1900363989 | 1981-03-06 | Inactive | |
| OKLAHOMA FACTORS INC. | — | 1900372703 | 1981-08-14 | Inactive | |
| OKLAHOMA FAN DISTRIBUTOR, INC. | — | 1900369523 | 1981-06-16 | Inactive | |
| OKLAHOMA FERTILIZER COMPANY, INC. | — | 2300369837 | 1981-06-22 | Inactive | |
| OKLAHOMA FILM COUNCIL, INC. | — | 2100377947 | 1981-11-23 | Active | |
| OKLAHOMA FOOD BROKERAGE COMPANY | — | 1900369059 | 1981-06-08 | Inactive | |
| OKLAHOMA FUND RAISERS, INCORPORATED | — | 1900373030 | 1981-08-20 | Inactive | |
| OKLAHOMA FUTURE FARMERS OF AMERICA ALUMNI ASSOCIATION, INC. | — | 2100369065 | 1981-06-08 | Active | |
| OKLAHOMA GAS PIPELINE COMPANY | — | 2300366511 | 1981-04-21 | Withdrawn | |
| OKLAHOMA GOLD & SILVER EXCHANGE, INC. | — | 1900369133 | 1981-06-09 | Inactive | |
| OKLAHOMA HIGH SCHOOL SOCCER ASSOCIATION, INC. | — | 2100371927 | 1981-07-30 | Active | |
| OKLAHOMA HILLS ENERGY, INC. | — | 1900371928 | 1981-07-30 | Inactive | |
| OKLAHOMA HISPANIC ASSOCIATION IN HIGHER EDUCATION | — | 2100374574 | 1981-09-18 | Active | |
| OKLAHOMA HISTORICAL FLYING MUSEUM, INC. | — | 2100379586 | 1981-12-28 | Active | |
| OKLAHOMA HOMEOPATHIC MEDICAL SOCIETY | — | 2100374087 | 1981-09-09 | Active | |
| OKLAHOMA HORSESHOER'S ASSOCIATION | — | 2100363251 | 1981-02-23 | Active | |
| OKLAHOMA HOTEL AND MOTEL ASSOCIATION, INC. | — | 1900371513 | 1981-07-22 | Dissolved | |
| OKLAHOMA HYDRAULIC WELL CONTROL, INC. | — | 1900361761 | 1981-01-23 | Inactive | |
| OKLAHOMA ICE COMPANY | — | 1900364089 | 1981-03-09 | Dissolved | |
| OKLAHOMA INDIAN ENERGIES AND DEVELOPMENT | — | 1900377432 | 1981-11-12 | Inactive | |
| OKLAHOMA INDIAN LEGAL SERVICES, INC. | — | 2100377669 | 1981-11-17 | Active | |
| OKLAHOMA INDUSTRIAL CASTING, INC. | — | 2300371690 | 1981-07-24 | Inactive | |
| OKLAHOMA INDUSTRIAL LUBRICANTS, INC. | — | 1900367019 | 1981-04-30 | Inactive | |
| OKLAHOMA INDUSTRIAL SILVER, INC. | — | 1900372012 | 1981-07-31 | Dissolved | |
| OKLAHOMA INDUSTRIES AUTHORITY (CANADIAN COUNTY) | — | 12200081 | 1981-01-22 | Active | |
| OKLAHOMA INTERNATIONAL ENERGY CORPORATION | — | 1900366385 | 1981-04-20 | Inactive | |
| OKLAHOMA INVESTORS, LTD. | — | 1900376105 | 1981-10-19 | Inactive | |
| OKLAHOMA JET CHARTERING, INC. | — | 1900379708 | 1981-12-29 | Inactive | |
| OKLAHOMA JET OPERATING COMPANY | — | 1900379709 | 1981-12-29 | Inactive | |
| OKLAHOMA JET, INC. | — | 1900367788 | 1981-05-14 | Inactive | |
| OKLAHOMA JUDO ASSOCIATION, INC. | — | 2100366552 | 1981-04-22 | Active | |
| OKLAHOMA LAND & EXPLORATION 1981 DRILLING PROGRAM, LTD. | — | 3300013232 | 1981-11-12 | Canceled | |
| OKLAHOMA LAND AND MINERAL COMPANY, INC. | — | 1900362945 | 1981-02-17 | Inactive | |
| OKLAHOMA LAND INVESTMENTS, INC. | — | 1900368822 | 1981-05-22 | Inactive | |
| OKLAHOMA LEASING COMPANY NO. 2, LTD. | — | 3300012714 | 1981-08-10 | Canceled | |
| OKLAHOMA LEASING COMPANY NO. 3, LTD. | — | 3300012715 | 1981-08-10 | Canceled | |
| OKLAHOMA LEASING COMPANY, LTD. | — | 3400013501 | 1981-12-21 | Canceled | |
| OKLAHOMA LEASING COMPANY, LTD. | — | 3300012713 | 1981-08-10 | Canceled | |
| OKLAHOMA LIGHTING DISTRIBUTORS, INC. | — | 1900375380 | 1981-10-02 | Active | |
| OKLAHOMA LIQUEFIED GAS OF CHICKASHA, INC. | — | 1900367722 | 1981-05-13 | Active | |