| Space Influences on the Terrestrial Environment | Academic & Science |
| Student Invention Through Education | Academic & Science |
| Science, Innovation, Technology, and Engineering | Academic & Science |
| School of Information Technology and Engineering, VIT University | Academic & Science |
| Secret In Their Eyes | Academic & Science |
| Stockholm Institute of Transition Economics | Academic & Science |
| Stanford Institute for Theoretical Economics | Academic & Science |
| System Integration, Test, and Evaluation | Academic & Science |
| Student Introduction To Engineering | Academic & Science |
| Society of Incentive Travel Executives | Business |
| Sindh Industrial Trading Estate | Business |
| Standard Income Tax on Employees | Business |
| Society of Insurance Trainers Educators | Business |
| SiteOne Landscape Supply, Incorporated | Business |
| Society for Information Technology and Teacher Education | Community |
| Society of Incentive and Travel Executives | Community |
| Society for Incentive Travel Excellence | Community |
| Satellite Instructional Television Experiment | Community |
| Sign In To Enter | Computing |
| School of Information Technology and Engineering | Computing |
| Systems Integration Testing Environment | Computing |
| Strategic Information Technology Effectiveness | Computing |
| Stormwater Innovative Technology Evaluators | Computing |
| Society for Information Technology in Education | Computing |
| Supernatural Intuitive Transmundane Entity | General |
| Site Impact Traffic Evaluation | General |
| Satellite Informational Television Entertainment | General |
| Substantial, Interactive, Targeted, and Easy | Governmental |
| Search for International Terrorist Entities | Governmental |
| Superfund Innovative Technology Evaluation | Governmental |
| Schreyer Institute for Teaching Excellence | Governmental |
| Smithsonian Institute Traveling Exhibition | Governmental |
| Shipboard Information, Training, and Entertainment | Governmental |
| Skills for Independence Transition and Employment | Governmental |
| Sindicato Independiente de Trabajadores de la Enseñanza | International |