August Bravais (23 August 1811, Annonay – 30 March 1863, Le Chesnay, France) was a French physicist, well known for his work in crystallography (the Bravais lattices, and the Bravais laws). Bravais also studied magnetism, the northern lights, meteorology, botanical geography, astronomy, and hydrography.

He studied at Collège Stanislas in Paris, then joined École Polytechnique in 1829. He became a naval officer at the end of his studies. He was a big adventurer, he embarked on the Finistere in 1832, then the Loiret and collaborated in hydrographic work along the Algerian Coast. He participated in the Recherche expedition, sent to Spitsbergen and to Lapland to help the Lilloise.

He taught a course in applied mathematics for astronomy in the faculty of sciences in Lyon from 1840. Then he succeded Victor Le Chevalier in the Chair of Physics, Ecole Polytechnique between 1845 and 1856, after which he was replaced by Hureau of Senarmont. He is best remembered for pointing out in 1845, that there are 14 unique Bravais lattices in three dimensional crystalline systems, adjusting the previously existent result (15 lattices) by Frankheim, obtained three years before. He published a memoire about crystallography in 1847. Co-founder of the Société météorologique de France, he joined the French Academy of Sciences in 1854.