Keilwerth is a German saxophone manufacturer founded in 1925 by Julius Keilwerth. The manufacturer originally began as primarily a stencil manufacturer for other prominent German horn builders; namely Adler and FX Huller.
By 1938 the company rose to be the largest instrument manufacturer in Germany employing 150 workers and exporting 2024 finished horns to 22 countries. Post war, however, the company was forced to relocate to Nauheim, Germany. Following this the company continued manufacturing horns using the same model designs until 1986.
In 1986 Keilwerth hired Jazz saxophonist Peter Ponzol to revamp their horn line for the modern jazz scene. By the end of the 1980's Keilwerth had produced their SX90 line of horns and gained endorsements from some of the biggest names in jazz at the time. From then the company changed hands several times until eventually in March 2010 it was bought by Buffet Crampon.