More than 50 years after the original Mitsunobu reaction reported in 1967, its catalytic and redox-neutral reactions have been developed. While the conventional method has problems such as the laborious separation of by-products and the explosive nature of azo reagents, the redox-neutral method solves these problems and its catalytic method enabled water as a sole by-product. This article describes the recent developments in the redox-neutral Mitsunobu reactions.