Joel Greenberg (born 1946) is an educational technology consultant and historian on the role of Bletchley Park in World War Two. Greenberg gained a PhD degree in numerical mathematics from the University of Manchester (UMIST) in 1973. For over 33 years, he worked for the Open University and held a number of director-level management positions. He lectures and writes about Bletchley Park and its role in World War II. He also conducts tours of the site. He is author of biographies about Gordon Welchman, a key figure at Bletchley Park during WWII, and Alastair Denniston, the first head of GCHQ. In 2017, he contributed a chapter to The Turing Guide on the German WWII Enigma machine.