Seigokan (正剛館) is the Goju-Ryu Karate-do organization founded in 1945 by Seigo Tada (1922-1997) Hanshi (8th Dan).

With its Hombu Dojo (headquarters) in Himeji, Japan, the Seigokan All Japan Karate-do Association (SAJKA) — its official name — has branches in Australia, Brazil, Canada, China (including Hong Kong and Macau), India, Italy, the Philippines, Portugal, Sri Lanka, the United States, England, Chile, Colombia, Indonesia and Venezuela.

Master Seigo Tada was a pupil of Chojun Miyagi and the head of the Karate Club at Ritsumeikan University.

The most well-known Seigokan member is Ms. Atsuko Wakai, four-time WKF Women's Kata World Champion.

The Italian Seigokan Chief Instructor is Shihan Francesco Cuzzocrea (6th Dan), from Reggio Calabria (Italy) The Indonesian Seigokan Chief Instructor is Shihan Dody Rochadi (6th Dan), from Jakarta (Indonesia).