Julius Klengel was a German cellist who is most famous for his études and solo pieces written for the instrument. He was the brother of Paul Klengel. A member of the Gewandhaus Orchestra of Leipzig at fifteen, he toured extensively throughout Europe as cellist and soloist of the Gewandhaus Quartet. His pupils include Guilhermina Suggia, Emanuel Feuermann, Gregor Piatigorsky and Alexandre Barjansky. See: List of music students by teacher: K to M#Julius Klengel.

Paul Klengel was a German violinist, violist, pianist, conductor, composer, editor and arranger. He was the brother of cellist Julius Klengel.