The thermal decomposition of methanol behind reflected shock waves with 1372 < T{sub 5} < 1842 K and 1.81 {times} 10{sup {minus}5} < {rho}{sub 5} < 2.15 {times} 10{sup {minus}5} mol/cm{sup 3} was studied by IR laser kinetic absorption spectroscopy and gas-chromatographic analysis of reaction products. The absorption profiles and product yields were satisfactorily modeled with a 26-reaction mechanism. The initial rate of decrease of IR absorption intensity and the product yields were very sensitive to the rate constants of the reactions CH{sub 3}OH + M = CH{sub 3} + OH + M, CH{sub 3}OH + H = CH{sub 3} + H{sub 2}O, CH{sub 3}OH + H = CH{sub 2}OH + H{sub 2}, and CH{sub 2}OH + M = CH{sub 2}O + H + M. The rate constant expression for the last reaction was derived.