Organizers
- Seattle University
- Seattle Youth Basketball
- Seattle Youth Symphony Orchestra
- Seattle's Littlest Performers
- Seattle's Performers LLC
- Sebastian Inlet Surf & Sport
- Sebastian Inlet Surf and Sport
- Seckman High School Tennis Club
- Second Presbyterian Church Memphis
- Second Star to the Right
- Second Wind Fund, Inc.
- Secret Meals
- Section 7 Project, Inc./ Trail of Terror
- Security Professional Development Institute,LLC
- Sedalia Runners Club
- Sedona Arts Center
- Sedona Golf Resort
- Sedro Woolley Little League
- See Jane Run
- SEED/The Foundation for Tigard Tualatin Schools
- SEEDS
- SEEDS Classic Rock 5K
- SEEK Ministries Inc.
- Seekers Wild
- Seffner Christian Academy
- Seguin Independent School District
- Seir Kierans NS
- Seits Incorporated
- Select University
- Self Help Center Inc.
- Selkirk Dolphins
- Sell Tennis Camps
- Selsdon Half Marathon
- Semaj 513 Basketball Camp
- Semiahmoo House Society
- Seminole Chamber of Commerce
- Seminole County Parks & Recreation
- Seminole County Parks and Recreation
- Seminole Sports
- SEMO Sports Productions
- SEMOY VTT CLUB
- Semper Fit Grand Prix Series
- Semurana Tennis
- SEND International
- Send Town Bike Club
- Seneca Falls Community Little League
- Seneca Janes
- Seneca Sailing Academy, Inc.
- Seni Nursing Assistant Training, LLC
- Senior Coastsiders
