Abstract The products and kinetics of the thermal decomposition of several methyl‐β‐hydroxyesters in m ‐xylene solution have been studied. It has been shown that all β‐hydroxyesters studied pyrolyze to form a mixture of methyl acetate and the corresponding aldehyde or ketone and that the decomposition follows first‐order kinetics and appears to be homogeneous and unimolecular. The rate pyrolysis of methyl‐3‐hydroxypropanoate, methyl‐3‐hydroxybutanoate, and methyl‐3‐hydroxy‐3‐methylbutanoate has been measured between 250 and 320°C. The relative rates of primary, secondary, and tertiary alcohols at 553 K are 1.0, 8.5 and 54.1, respectively. The absence of large substituent effects indicates that little charge separation occurs during the breaking of carbon–carbon single bond. The activation entropy is compatible with a semipolar six‐membered cyclic transition state postulated for other β‐hydroxy compounds. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 92–96, 2007