Phenol (systematically named Benzenol, also called carbolic acid or phenolic acid) is an aromatic organic compound with the molecular formula C₆H₅OH. It is a white crystalline solid that is volatile. The molecule consists of a phenyl group (−C₆H₅) bonded to a hydroxy group (−OH). Mildly acidic, it requires careful handling because it can cause chemical burns.

Phenol was first extracted from coal tar, but today is produced on a large scale (about 7 billion kg/year) from petroleum-derived feedstocks. It is an important industrial commodity as a precursor to many materials and useful compounds. It is primarily used to synthesize plastics and related materials. Phenol and its chemical derivatives are essential for production of polycarbonates, epoxies, Bakelite, nylon, detergents, herbicides such as phenoxy herbicides, and numerous pharmaceutical drugs.