The DMREF sponsored a three-dimensional (3D) microstructure workshop August 18-20, 2023.  This was our most successful workshop so far, in the sense that we exceeded our limit for the maximum number of participants (60). The workshop consisted of three types of presentations.  Roughly one quarter of the presentations were about state of the art 3D materials research. It was noteworthy that one of the invited speakers this year, Ashley Spear, an associate professor at the University of Utah, attended and earlier version of the workshop as a graduate student.  Another quarter of the presentations were tutorials illustrating the capabilities and uses of the open source software for 3D analysis and modeling, Dream.3D.  The final half of the workshop consisted of practical sessions in which participants work on their own projects with the guidance of the organizers.  The workshop enables participants to adopt software tools and scientific methods that are direct outcomes of DMREF research.