| Optimum Thermal Interpolation System | Academic & Science |
| Organization of Teratology Information Specialists | Business |
| Online Teacher Information System | Community |
| On Time In School | Community |
| Online Technology and Instructional Sessions | Computing |
| Outstanding Technology Innovative and Service | Computing |
| Optional Transponder Installation Saddle | Electronics |
| Organize This Important Stuff | General |
| Organizing This Important Stuff | General |
| Oil Tank Inspection And Surveillance | General |
| Otis Of Thee I Sing | General |
| Optimal Traveling Independent Space | General |
| Optical Transpose Interconnection System | General |
| Occurrence Tracking Information System | General |
| Only The Illuminati Succeed | General |
| Our Time Is Short | General |
| Operations Terminal Information System | General |
| Optimal Thermal Interpolation System | General |
| Outside The Inner Sanctum | General |
| Optical Thermal Imaging System | General |
| Only The Illuminati Stands | General |
| Overhead Travel Information System | General |
| Online Travel Information System | General |
| Online Touring Information System | General |
| Oil Tank Inspection System | Governmental |
| Offender Tracking and Information System | Governmental |
| Offender Tracking Information System | Governmental |
| Online Tracking Information System | Governmental |
| Office of Transportation Infrastructure and Sustainability | Governmental |
| Online Transportation Information System | Governmental |
| Operative Term Is Stimulate | Medical |
| Organ Transplant Information System | Medical |
| Only The Illuminati Survives | Messaging |
| On Time In Spec | Space Science |
