Ikuma Dan (團 伊玖磨 Dan Ikuma?, 7 April 1924 – 17 May 2001) was a Japanese composer.
Dan was born in Tokyo, the descendant of a prominent family, his grandfather Baron Dan Takuma having been President of Mitsui before being assassinated in 1932. He graduated from Aoyama Gakuin and Tokyo National University of Fine Arts and Music in 1946. One of his teachers was Kosaku Yamada.
During his career he completed six symphonies, all recorded and released on the Decca label in Japan, and wrote seven operas as well as a number of filmscores, and many songs. He wrote celebratory music for the Japanese imperial family, actively promoted cultural exchange with China (from 1979 until his death in Suzhou, China, in 2001), and received the commission to write an opera (Takeru) for the 1997 opening of the New National Theatre, Tokyo, Japan's main opera house.
Dan is known in Japan for his 1951 opera Yūzuru (Twilight Crane), which is regularly revived there.