This chapter compiles data for self-diffusion in thorium (Th), uranium (U), and plutonium (Pu) actinide group metals. Pre-exponential factor (D0) and activation enthalpy (Q) data are listed. The temperature range given is the range over which measurements were made and used to calculate the values of D0 and Q. Structural investigation results are also provided for these actinide group metals. Experimental methods include mechanical sectioning, lathe sectioning, grinder sectioning, and autoradiographic experiments.