Léonce Rosenberg (1879 – 1947) was a French art dealer born in Paris, France. He started his career as an art dealer in 1901. In the early years of his career, he worked for the Galerie Durand-Ruel. He later opened his own gallery, called the Galerie Léonce Rosenberg.

Rosenberg was one of the first art dealers to recognize the talent of Pablo Picasso. He began buying Picasso’s paintings in 1905 and continued to do so for the rest of his life. Rosenberg was also a friend and patron of other artists, including Henri Matisse, Georges Braque, and Juan Gris.

Rosenberg’s gallery was very successful. He organized many important exhibitions of modern art, including the first solo exhibitions of Picasso and Matisse in Paris. Rosenberg died in 1947.