A review of ICRF heating experiments on tokamaks is presented. This method of radio frequency heating has proven to be efficacious and has been projected as a viable method for future machines such as INTOR and CIT. ICRF heating experiments on JET, ASDEX, TEXTOR, and JT-60 are part of an ongoing program to further understand the physics of the heating process and the physics of tokamak operation with auxiliary heating, particularly the effect on energy confinement.