Silvius Leopold Weiss (1687 - October 16, 1750) was a German composer and lutenist. Born in Breslau, the son of Johann Jacob Weiss , also a lutenist, he served at courts in Breslau, Rome, and Dresden, where he died. Until recently, he was thought to have been born in 1686, but recent evidence suggests that he was in fact born the following year.

Weiss was one of the best-known and most technically accomplished lutenists of his day. He was also a prolific composer for the instrument, and wrote around 600 pieces for it. Many of his works are grouped into 'sonatas' (not to be confused with the later classical sonata, based on sonata form) or suites, which consist mostly of baroque dance pieces. Weiss also wrote chamber pieces and concertos, but unfortunately no complete example survives.

In later life, Weiss became a friend of J.S. Bach. The two were said to have competed in improvisation, as the following account by J. F. Reichardt describes:

"Anyone who knows how difficult it is to play harmonic modulations and good counterpoint on the lute will be surprised and full of disbelief to hear from eyewitnesses that Weiss, the great lutenist, challenged J. S. Bach, the great harpsichordist and organist, at playing fantasies and fugues."