| Southeastern College | South Carolina |
| Southeastern Illinois College | Illinois |
| Southeastern Institute of Manufacturing Technology | South Carolina |
| Southeastern Louisiana University | Louisiana |
| Southeastern Oklahoma State University | Oklahoma |
| Southeastern Technical College | Georgia |
| Southeastern University | Florida |
| Southern Adventist University School of Computing | Tennessee |
| Southern AgCredit | |
| Southern Arkansas University Department of Mathematics and Computer Science | Arkansas |
| Southern Arkansas University Tech | Arkansas |
| Southern Cal Telecom, Inc. | California |
| Southern California Institute of Technology | California |
| Southern California Israel Chamber of Commerce | |
| Southern California Linux Expo | |
| Southern California Marine Institute | |
| Southern California Orthopedic Institute | |
| Southern California OS/2 User Group | California |
| Southern California University Health Sciences | California |
| Southern California Users Group | California |
| Southern Colorado Computer Services | Colorado |
| Southern Connecticut State University | Connecticut |
| Southern Consulting, LLC | Alabama |
| Southern Crossroads | Georgia |
| Southern Data Automation, Inc. | Alabama |
| Southern Digital Consulting | |
| Southern Electronics | Louisiana |
| Southern Illinois Linux Users Group | Illinois |
| Southern Illinois University Carbondale Computer Science | Illinois |
| Southern Illinois University Carbondale Mathematics | Illinois |
| Southern Illinois University Edwardsville Department of Computer Science | Illinois |
| Southern Illinois University Edwardsville Mathematics and Statistics | Illinois |
| Southern Illinois University System | Illinois |
| Southern Made | |
| Southern Methodist College | South Carolina |
| Southern Methodist University Computer Science Department | Texas |
| Southern Methodist University Department of Mathematics | Texas |
| Southern Nazarene University | Oklahoma |
| Southern New Hampshire University | New Hampshire |
| Southern NH Software | New Hampshire |
| Southern Oregon University Computer Science | Oregon |
| Southern Oregon University Mathematics | Oregon |
| Southern States University | California |
| Southern Technical College | Florida |
| Southern Technologies, LLC | Louisiana |
| Southern Technology Group | Alabama |
| Southern Technology Professional Consulting Service | |
| Southern Tide Media | |
| Southern University and A&M College | Louisiana |
| Southern University at Shreveport | Louisiana |