Old English Mastiff Club
- Breed standard, health information, newsletter, club history, show updates, forum, and their code of ethics. United Kingdom.
- http://www.mastiffclub.com/

Redwood Empire Mastiff Club
- Events calendar, show news, membership information, and a breeders' directory. West Coast.
- http://www.redwoodempiremastiffclub.org/

Mastiff Club of Victoria
- Information about health and temperament, list of club activities and events, application form, and a photograph gallery. Victoria, Australia.
- http://www.mastiff.com.au/

Mastiff Club of America
- Information about their National Specialty, rescue and health committees, frequently asked questions, and breed information. They are the American Kennel Club parent club for the breed.
- http://www.mastiff.org/