Propylene glycol (IUPAC name: propane-1,2-diol) is a synthetic organic compound with the chemical formula C₃H₈O₂. It is a viscous, colourless liquid which is nearly odourless but possesses a faintly sweet taste. Chemically it is classed as a diol and is miscible with a broad range of solvents, including water, acetone, and chloroform.

Propylene glycol is used as a chemical feedstock for the production of unsaturated polyester resins or other polymers. It is also used as a humectant, solvent, and preservative in food and for tobacco products.

Propylene glycol is also used in various edible items such as coffee-based drinks, liquid sweeteners, ice cream, whipped dairy products and soda.