Triethylene Glycol (TEG) is a viscose, odorless and colorless chemical liquid with chemical formula C6H14O4.

TEG is produced as a co-product from the reaction between ethylene oxide and water. It is miscible with water and soluble in ethanol, acetone, acetic acid, glycerine, pyridine and aldehydes. It is slightly soluble in diethyl ether, and insoluble in oil, fat and most hydrocarbons.