Triethylene glycol, TEG, or triglycol is a colorless odorless viscous liquid with molecular formula HOCH2CH2OCH2CH2OCH2CH2OH. It is used as a plasticizer for vinyl polymers.

Triethylene glycol is a member of a homologous series of dihydroxy alcohols. It is a colorless, odorless and stable liquid with high viscosity and a high boiling point. Apart from its use as a raw material in the manufacture and synthesis of other products, TEG is known for its hygroscopic quality and its ability to dehumidify fluids.