Triolein (glyceryl trioleate) is a symmetrical triglyceride derived from glycerol and three units of the unsaturated fatty acid oleic acid. Most triglycerides are unsymmetrical, being derived from mixtures of fatty acids. Triolein represents 4–30% of olive oil.

Triolein is also known as glyceryl trioleate and is one of the two components of Lorenzo's oil.

The oxidation of triolein is according to the formula:

This gives a respiratory quotient of 57/80 or 0.7125. The heat of combustion is 8,389 kcal (35,100 kJ) per mole or 9.474 kcal (39.64 kJ) per gram. Per mole of oxygen it is 104.9 kcal (439 kJ).