In this work, the transformation of several phenolic compounds by peroxymonosulfate (PMS) in the presence of iodide (I-) was investigated with a focus on the potential formation of iodinated aromatic products of concerns. The addition of I- greatly enhanced the transformation of phenol and bisphenol A (BPA) by PMS, and this enhancement was strongly influenced by several factors (i.e., I- and PMS concentrations and solution pH). This result could be well explained by the competition reactions of hypoiodous acid (HOI) formed in situ with phenols vs PMS under various conditions. Five iodophenols were identified from HOI reaction with phenol, and four iodinated BPA (including mono-, di-, tri- and tetra-iodinated BPA) together with two bond-cleavage iodinated aromatic products were detected in the case of BPA. Reaction pathways mainly involving stepwise substitution of HOI on phenol and BPA were proposed, and beta-scission of isopropyl moiety also took place for iodinated BPA. Moreover, evolution of these iodinated aromatic products from phenol and BPA in the PMS/I- system was monitored, and a lower pH or a higher [I-]:[ PMS] ratio favored their formation. Comparatively, I- accelerated the transformation of catechol and hydroquinone by PMS but with negligible formation of iodinated aromatic products, where these two phenols underwent oxidation rather than substitution in the presence of HOI formed in situ. This work clearly demonstrates a high potential of forming iodinated aromatic products during treatment of phenolic compounds by PMS in the presence of I-, which depends on the reaction conditions as well as the reactivity and pathway of HOI.