Danzan Ryu (檀山流, "Sandalwood Mountain School" from a Chinese name for Hawaii) is a Ryu of jujutsu founded by Professor Seishiro Okazaki (1890-1951) in Hawaii. It is one of the most ubiquitous jujutsu traditions in the United States, and on the West Coast in particular. It's governing body is the AJJF which stands for American Judo and Jujitsu Federation. The AJJF was founded by John Cahill, Bud Estes, Ray Law, and Richard Rickerts in 1958.

Training in Danzan Ryu includes methods of kappo and seifukujutsu.