Naphthol AS is an organic compound with the formula C<sub>10</sub>H<sub>6</sub>(OH)C(O)NHC<sub>6</sub>H<sub>5</sub>. It is the anilide of 3-hydroxy-2-carboxynaphthalene. Many analogous compounds are known, designated with a differing suffix. For example, in Naphthol AS-OL, the aryl substituent on nitrogen is C<sub>6</sub>H<sub>4</sub>-2-OCH<sub>3</sub>. These compounds are used as coupling partners in the preparation of some azo dyes.
In 1911, it was found to be a good precursor to dyes for wool by chemists at K. Oehler Anilin- und Anilinfarbenfabrik Offenbach.