2,4,6-Trinitrobenzoic acid (TNBA) is an organic compound with the formula (O<sub>2</sub>N)<sub>3</sub>C<sub>6</sub>H<sub>2</sub>CO<sub>2</sub>H. It is a high explosive nitrated derivative of benzoic acid.
2,4,6-Trinitrobenzoic acid is prepared by oxidation of 2,4,6-trinitrotoluene (TNT). It is formed by oxidation of TNT and nitric acid with chlorate and with dichromate.
Upon heating, 2,4,6-trinitrobenzoic acid undergoes decarboxylation to give 1,3,5-trinitrobenzene. Reduction with tin gives 2,4,6-triaminobenzenoic acid, a precursor to phloroglucinol (1,3,5-trihydroxybenzene).