Antoine-Joseph "Adolphe" Sax (November 6, 1814 – February 4, 1894) was a Belgian musical instrument designer and musician (clarinetist), best known for inventing the saxophone.

Adolphe Sax was born in Dinant in Wallonia, Belgium. His father, Charles-Joseph Sax, was an instrument designer himself, who made several changes to the design of the horn. Adolphe began to make his own instruments at an early age, entering two of his flutes and a clarinet into a competition at the age of fifteen. He subsequently studied those two instruments at the Royal School of Singing in Brussels.

Having left the school, Sax began to experiment with new instrument designs, while his father continued to produce conventional instruments to bring money into the household. Adolphe's first important invention was an improvement of the bass clarinet design which he patented at the age of twenty.