SMU
- Finnish Seafarers' Union
- SMU Mustangs
- Saint Monica University
- Samuel Merritt University
- Sangmyung University
- Scandinavian Monetary Union
- Sefako Makgatho Health Sciences University
- Shanghai Maritime University
- Sikkim Manipal University
- Singapore Management University
- Somray language
- Source measure unit
- Southeastern Massachusetts University
- Southern Medical University
- Southern Methodist University
- Special mission unit
- St. Martin's University
- St. Matthew's University
- St. Michaels University School
- Suburban Multiple Unit (Queensland Rail)
- Suriname Men United
- Svenska Missionskyrkans Ungdom Scout
- Swansea Metropolitan University
- System Management Unit