Léon Becker was a Belgian botanist, painter, naturalist, and arachnologist.

From a young age, he became passionate about entomology, with a particular interest in arachnology. He is the author of the first studies on Belgian spiders. Between 1882 and 1896, he published four volumes entitled Les Arachnides de la Belgique, which he illustrated himself. His lithographs are of very high quality.

He also studied Dutch, German, Moldavian and Hungarian fauna.