Rudolph "Rudy" Cornelius Wiedoeft (January 3, 1893 - February 18, 1940) was a U.S saxophonist.

Born in Detroit, Michigan, the son of German immigrants, at a young age Weidoeft started playing with his family orchestra, first on violin, then on clarinet. He moved to New York City and switched to saxophone, then still an unusual instrument. He became known as a virtuoso saxophonist in the 1910s, made many recordings for different record labels, and did much to popularize the saxophone as an instrument in the U.S. His instrument was the C-melody sax, a variety which became uncommon after the 1930s.

His style was noted for very rapid runs of notes in between long lush leggato phrases in a ragtime influenced style. While he incorporated some elements of early jazz into his playing, he remained stylistically a pre-jazz artist. Some of his original compositions were hits in their day, notably Valse Erica, Valse Llewellyn, and Saxophobia.

He remained a very popular entertainer into the 1920s and performed regularly on radio, but his style started to sound more and more dated to the public as his carrer continued into the 1930s. He worked for a while in Rudy Vallee's band, then for a while in France. Rudy Weidoeft died after being stabbed by his wife.