Phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl functional group (-OH) attached to an aromatic hydrocarbon group. The simplest of the class is phenol (C₆H₅OH). Although similar to alcohols, phenols have unique properties including relatively higher acidities due to the aromatic ring tightly coupling with the oxygen and a relatively loose bond between the oxygen and hydrogen. The acidity of the hydroxyl group in phenols is commonly intermediate between aliphatic alcohols and carboxylic acids. Loss of a positive hydrogen from the hydroxyl group of a phenol forms a negative phenolate ion.

Phenols are often germicidal and are sometimes used in formulating disinfectants.

Many phenolic compounds possess estrogenic activity.