Biotherm is a French luxury skin care company owned by L'Oréal under the Luxury Products division. Biotherm was acquired by L'Oréal in 1970.

Biotherm originated from mineral water. In early 20th century, the French biologist Mme Jeanine Marissal discovered mineral thermal spring waters under Pyrenees mountain in the southern part of France which contained thermal plankton, supposedly a key to healthy skin and a potent skin rejuvenator. She applied for intellectual property rights on this discovery. In 1952, intellectual property rights was acquired and she used it in skin care products. Thus, therm in Biotherm comes from thermal plankton, an ingredient found in all Biotherm products. Bio comes from the profession of the founder biologist.