Lanthanum chloride is the inorganic compound with the formula LaCl3. It is a common salt of lanthanum which is mainly used in research. It is a white solid that is highly soluble in water and alcohols.

One application of lanthanum chloride is the removal of phosphate from solutions via precipitation, e.g. in swimming pools to prevent algae growth and other wastewater treatments. It has also shown use as a filter aid and an effective flocculent. Lanthanum chloride is also used in biochemical research to block the activity of divalent cation channels, mainly calcium channels. Doped with cerium, it is used as a scintillator material.

In organic synthesis, lanthanum trichloride functions as a mild Lewis acid for converting aldehydes to acetals.

The compound has been identified as a catalyst for the high pressure oxidative chlorination of methane to chloromethane with hydrochloric acid and oxygen.