The kinetics of the reaction of O3 with the aromatic vicinal diols 1,2-benzenediol, 3-methyl-1,2-benzenediol, and 4-methyl-1,2-benzenediol have been investigated using a relative rate technique. The rate coefficients were determined in a 1080-L smog chamber at 298 K and 1 atm total pressure of synthetic air using propene and 1,3-butadiene as reference compounds. The following O3 reaction rate coefficients (in units of cm3 molecule−1 s−1) have been obtained: k(1,2-benzenediol) = (9.60 ± 1.12) × 10−18, k(3-methyl-1,2-benzenediol) = (2.81 ± 0.23) × 10−17, k(4-methyl-1,2-benzenediol) = (2.63 ± 0.34) × 10−17. Absolute measurements of the O3 rate coefficient have also been carried out by measuring the decay of the dihydroxy compound in an excess of O3. The results from these experiments are in good agreement with the relative determinations. Atmospheric implications are discussed.