The transient absorption spectrum of the tert-butoxyl radical in the UV region was obtained by the laser flash photolysis technique. The rate constants for beta-scission and self-termination reactions of tert-butoxyl radicals were measured in five solvents; the Arrhenius parameters of the rate constant for beta-scission k(beta) were determined. It was shown that both the solvent polarity and ability for hydrogen bonding accelerate the reaction of beta-scission. The solvent effect on the rate constant of the p-scission reaction is discussed in terms of a simple Onzager-Betcher model, a point dipole model, and a model of the H-bonded complex of the radical with the solvent molecule.