John Kaizan Neptune (born November 13, 1951 in Oakland, California, United States) is an American player and builder of the shakuhachi (Japanese bamboo flute). He is known particularly for his use of the instrument in non-traditional contexts, such as jazz and cross-cultural music. He also makes shakuhachi and other bamboo instruments at his home workshop in the Japanese countryside. John Kaizan Neptune has recorded 21 records since 1979.