Refill Friction Stir Spot Welding (RFSSW) as a novel joining technique has the ability to open the door to allow for the joining of materials previously thought difficult or impossible to join by conventional processes. RFSSW incorporates the friction welding physics of traditional linear friction stir welding and has already proven very effective in joining aluminum and similar materials. In recent years much of the development has been funded by aerospace and automotive industries. However, studies regarding the thermomechanical outcomes of RFSSW are very limited in both quantity and scope. Previous studies have investigated thermal and mechanical models separately; however, the majority of these studies were within the scope of Linear Friction Stir Welding (FSW). Further research into the thermomechanical characteristics are critical to the development of RFSSW. This research seeks to improve the feasibility by which to digitally model, and predict the thermomechanical characteristics created during the RFSSW process. This research utilized Finite Element Analysis (FEA) to help realize its objective. The objective of the investigation was to developed realistic predictive models for RFSSW on Aluminum lap joints. Several models, iterations, and weld orders were developed. Models were validated in part by previous work done by Wichita State University. Accurate thermal models where developed and the mechanical models developed (while not numerically accurate) where accurate when comparing distortion caused by different welds orders. This indicates that with further development and research fully articulate predictive models could be developed. This would greatly advance the field RFSSW as experiments could be realized digitally before moving to the physical stage, saving time, money, and resources.