The isomerization of 1-methylcyclohexene-1 (1MCH1), 3-methylcyclohexene-1 (3MCH1), 4-methylcyclohexene-1 (4MCH1), and methylenecyclohexane (MECH) over γ-alumina in 180°C in a batch reactor leads predominantly to double bond migration. The migration occurs stepwise according to the scheme: MECH1MCH13MCH14MCH1. The rates are first order in the reactants. The overall relative rate constants are calculated, The composition of the equilibrium mixture of the four isomers at 180°C in the vapor phase consists of 73.4% 1MCH1, 10.7% 3MCH1, 14.1% 4MCH1, and 1.7% MECH. © 1979 Academic Press, Inc. All rights reserved.