Louis Lang was a German-American painter.

He was born as Joseph Aloysius Lang in Waldsee, Duchy of Württemberg. His father, a historical painter, wished him to become a musician, but his taste was for art. At the age of 16, he executed pastels with success. He studied at Stuttgart and Paris, and settled in the United States in 1838, his studio being for several years in Philadelphia. He spent the years 1841 to 1845 in Italy, and moved to New York City in 1845, where he resided, with frequent visits to Europe. He was elected a National Academician in 1852, and was a member of the Artists' Fund Society.