The kinetics of oxidation of substituted 2‐furaldehydes by quinolinium dichromate in sulfuric acid, using 50% acetic acid as the solvent, was studied. The rate of the reaction was first order in each of the substrate, oxidant and acid. The kinetic data are discussed with reference to the aldehyde hydration equilibria. The kinetic results support a mechanistic pathway proceeding via a rate‐determining oxidative decomposition of the chromate ester of the aldehyde hydrate. Copyright © 2003 John Wiley & Sons, Ltd.