Jay Randall Sandke (born May 5, 1949 in Chicago, Illinois) is a jazz trumpeter and guitarist.

While a student at Indiana University in 1968, he and Michael Brecker started a jazz-rock band (Mrs. Seamon's Sound Band) that performed at the Notre Dame Collegiate Jazz Festival. He was invited to be a member of the backing band for rock singer Janis Joplin, but a throat problem kept him from performing. Despite a successful operation on his throat, he gave up the trumpet, moved to New York City, and played guitar for the next ten years. When he returned to the trumpet, he became a member of the Nighthawks Orchestra led by Vince Giordano, followed by membership in Bechet's Legacy led by Bob Wilber. From 1984–1985, he was part of Benny Goodman's last band.

Sandke remarks in the liner notes to The Subway Ballet: "Okay – I worked with Benny Goodman, but so did Fats Navarro and Herbie Hancock and nobody refers to them as 'swing musicians'. ...Being thus labeled is somewhat akin to being called a child molester in that the tag never seems to go away, and both can be equally deleterious to one's career." He has recorded over twenty albums as a leader, ranging from revisitings of music from the 1920s and 1930s to explorations of contemporary idioms in the company Michael Brecker, Kenny Barron, Marty Ehrlich, Bill Charlap, and Uri Caine. He became interested in exploring dissonant, nonstandard harmonies that lie outside of conventional triadic harmony, creating a musical theory of what he calls "metatonality", a harmonic system outlined in his book Harmony for a New Millennium.

He has led the New York All-Stars with Dan Barrett and Ken Peplowski, the Metatonal Band with Marvin Smith and Ted Rosenthal, and has done arrangements for the Carnegie Hall Jazz Orchestra. His writings include a method book about his "metatonal" approach to harmony. He has a brother, Jordan Sandke, who is a trumpeter. Both brothers played in the Widespread Depression Jazz Orchestra.

His albums include Trumpet After Dark, a jazz-with-strings album that uses Renaissance viols instead of modern violins. Inside Out and Outside In bring together mainstream jazz musicians such as Ken Peplowski and avant-garde jazz musicians Ray Anderson and Uri Caine. His work appeared in the movies The Cotton Club, Bullets over Broadway, and The Curse of the Jade Scorpion.