UMLGraph was developed and is being maintained by Diomidis Spinellis. Andrea Aime has contributed the functionality for adding UML diagrams to javadoc pages, for inferring relationships, and for multiple diagram views.

In addition, the following individuals have contributed useful comments and code. UMLGraph would not be in its current state without their contributions.

- Nascif Abousalh-Neto
- Roger Alexander
- Panagiotis Astithas
- Bernd Blacha
- Yves Bossel
- Maxim Butov
- David P. Caldwell
- Anthony Callegaro
- Cimballi
- Dirk Datzert
- Christophe Deneux
- Nick Efthymiou
- Georgios Gousios
- Antti Hakala
- Art Hampton
- Øyvind Jergan
- Scott Johnson
- Gunho Kim
- Nikita Kozlov
- Trustin Lee
- Joshua Lim
- Vadim Nasardinov
- Laird Nelson
- Bernd Onasch
- Sébastien Pierre
- Olek Poplavskyy
- Alessandro Riva
- Arnaud Rogues
- Soraya Santana de la Fe
- Jonathan R. Santos
- Jan Schlüter
- Sebastian Setzer
- Jörn Guy Süß
- Andreas Studer
- Przemyslaw Szufel
- Ivan F. Villanueva B.
- Przemyslaw Wesolek
- Franz Wilhelmstoetter
- Zhigang Xie