Alkylphenols are a family of organic compounds obtained by the alkylation of phenols. The term is usually reserved for commercially important propylphenol, butylphenol, amylphenol, heptylphenol, octylphenol, nonylphenol, dodecylphenol and related "long chain alkylphenols" (LCAPs). Methylphenols and ethylphenols are also alkylphenols, but they are more commonly referred to by their specific names, cresols and xylenols.

The long-chain alkylphenols are prepared by alkylation of phenol with alkenes: C6H5OH + RR'C=CHR" → RR'CH-CHR"-C6H4OH
In this way, about 500M kg/y are produced.