Thiophanate-methyl is an organic compound with the formula C<sub>6</sub>H<sub>4</sub>(NHC(S)NH(CO)OCH<sub>3</sub>)<sub>2</sub>. The compound is a colorless or white solid, although commercial samples are generally tan-colored. It is prepared from o-phenylenediamine. It is a widely used fungicide used on tree, vine, and root crops. In Europe it is applied to tomato, wine grapes, beans, wheat, and aubergine.
Methods for its analysis have received considerable attention. It is commonly used to treat botrytis bunch rot and gray mold caused by Botrytis cinerea strawberry in California. Thiophanate-methyl acts as a fungicide via its primary metabolite carbendazim.