Conducting on-board training (OBT) while crew are in space allows training for new and complex tasks and helps remind crew of previous training done on the ground. The ESA-sponsored Virtual Reality - On-Board Training (VR-OBT) project aims to perform training activities on the ISS via a virtual reality Head Mounted Display (HMD), which enables visualization and interaction with complex 3D models. This technology demonstration will evaluate the compatibility of VR equipment with the ISS environment, test how well real-time space-to-ground collaboration can occur, and compare the efficiency of training delivery via VR relative to standard training methods.