Major League Baseball Players Alumni Association
- Organization of former players. Features information, history, and news of the organization's activities.
- http://www.mlb.com/mlb/features/alumni/

American Amateur Baseball Congress
- Coordinates play among US leagues in seven age brackets, from sub-teens through adults. Includes rules, tournament dates, and list of regions and age divisions.
- http://www.aabc.us/

Amateur Baseball Umpire Association
- An umpire information center. Umpire associations, umpire equipment, umpire rules; a resource center for umpires to find and share information.
- http://www.umpire.org/

American Federation of Umpires(AFU)
- Group of baseball and softball umpires who share the common goal of consistent improvement in their officiating skills and knowledge of the game. Features clinics, a newsletter, and various resources.
- http://www.americanfederationofumpires.com/

The United States Amateur Baseball Association.
- The USABA is here for the promotion and development of the players and fans in youth baseball pastseason tournament competitions at state, regional, and national level.
- http://www.usaba.com/

American Baseball Coaches Association (ABCA)
- A nonprofit organization having more than 5,000 members, including coaches from every state in the country and over 200 international members.
- http://www.abca.org/