Tetrahydrophthalic anhydride is an organic compound with the formula C<sub>6</sub>H<sub>8</sub>C<sub>2</sub>O<sub>3</sub>. The compound exists as two isomers, this article being focused on the more common cis isomer. It is a white solid that is soluble in organic solvents.
Tetrahydrophthalic anhydride, the cis isomer, is prepared by the Diels-Alder reaction of butadiene and maleic anhydride.
Tetrahydrophthalic anhydride is a precursor to other compounds including the dicarboxylic acid tetrahydrophthalic acid as well the tetrahydrophthalimide, which is a precursor to the fungicide Captan. It is also a precursor to 1,2,3,4-butanetetracarboxylic acid.