Air Liquide S.A. (French pronunciation: ​[ɛʁ likid]; /ˌɛər lɪˈkiːd/; literally "liquid air"), is a French multinational company which supplies industrial gases and services to various industries including medical, chemical and electronic manufacturers. Founded in 1902, after Linde it is the second largest supplier of industrial gases by revenues and has operations in over 80 countries.[2] It has headquarters at the 7th arrondissement of Paris, France.[3] Air Liquide owned the patent for Aqua-Lung until it expired.

Although Air Liquide's headquarters are in Paris, France, it also has major sites in Japan (ALL) and Houston, TX and Newark, DE, USA, Frankfurt, Shanghai and Dubai. There is an emphasis on research and development (R&D) throughout the Air Liquide company. R&D targets the creation of not only industrial gases, but also gases that are used in products such as healthcare items, electronic chips, foods, and chemicals. The major R&D groups within Air Liquide focus on analysis, bioresources (foods and chemicals), combustion, membranes, modeling, and the production of hydrogen (H2) gas.

The company is a component of the Euro Stoxx 50 stock market index.[4] As of 2019, the company is ranked 500 in the Fortune Global 500.