Alexandre Brongniart (1770–1847) was a French chemist, mineralogist, and zoologist, who collaborated with Georges Cuvier on a study of the geology of the region around Paris. He was the son of the architect Alexandre-Théodore Brongniart and father of the botanist Adolphe Théodore Brongniart.

Born in Paris, he was an instructor at the École de Mines (Mining School) in Paris and director of the porcelain works at Sèvres. He introduced a new classification of reptiles and wrote several treatises on mineralogy and the ceramic arts. He also made an extensive study of trilobites and made pioneering contributions to stratigraphy by developing fossil markers for dating strata.

Brongniart was also the founder of the French National Museum of Ceramics (Le musée national de Céramique), having been director of the Sèvres Porcelain Factory from 1800 to 1847. In 1823, he was elected a foreign member of the Royal Swedish Academy of Sciences.