- Swinerton Builders
- Swisher Hygiene
- Swiss Cleaners
- Sylvan Learning
- Sylvia's Beauty Salon
- Symbol Technologies
- Symmetry
- Symons Corporation
- Symphony Mobilex
- Synchronicity
- Syncor International
- Syncor International Corporation
- Synergy Bank
- Synergy Gas Corporation
- Synergy Management Solutions
- Synovate
- Synovus Securities
- Sysco Food Services
- Systel
- System Scale Corporation
- System Solutions
- Systems Management
- Systems Plus
- Systems Unlimited
- Szechuan Garden
- Szechuan Restaurant
- Szechwan Chinese Restaurant