The kinetics of the thermal decomposition of aluminum alkyls, in the presence of a carrier gas, to produce aluminum have been studied for tri-n-propyl aluminum, tri-n-butyl aluminum, and tri-i-butyl aluminum in the temperature range 540 to 740 K. The reactions were found to be first order with respect to alkyl; activation energies for reaction and diffusivities were obtained from the experimental data by fitting an equation for a heterogeneous reaction. The deposited aluminum was found to have a carbon content which increased with temperature. Gaseous products of reaction were observed to contain hydrocarbons other than the principal olefin, although these other hydrocarbons were present in only small amounts in the case of tri-i-butyl aluminum.