Joseph Louis Diorio (August 6, 1936 – February 2, 2022) was an American jazz guitarist. He performed with Sonny Stitt, Hal Crook, Eddie Harris, Ira Sullivan, Stan Getz, Pat Metheny, Horace Silver, Anita O’Day, and Freddie Hubbard. In recent years he also recorded albums with modern performers including Robben Ford, Gary Willis, David Becker and Mick Goodrick.

Following in the footsteps of an uncle, Diorio took up the guitar, studying formally in the early 1950s at a local music school. He worked for a while with local bands, but in the early 1960s he ventured into New York City, where he played with several jazz musicians.

In April 2005 he struggled to regain the full use of his left hand following a stroke he suffered at his West Coast residence in San Clemente.

Diorio taught at the University of Southern California. He was also one of the first instructors for the Guitar Institute of Technology. He published several instructional books and videos, and released ten albums under his name.

He died on February 2, 2022, at the age of 85.