Effective and reliable computational models would greatly enhance the study of energy dissipation during the friction stir spot welding (FSSW) process. Approaches for the computational modeling of the FSSW process, however, are still under development, and much work is still needed, particularly the application of explicit finite element (FE) codes for a verifiable simulation. The objectives of this work are to develop an FE modeling of FSSW of 6061-T6 aluminum alloy and analyze energy generation during the welding process. In this work, a three dimensional (3-D) FE coupled thermal-stress model of FSSW process has been developed in Abaqus/Explicit code. Rate dependent Johnson-Cook material model is used for elastic-plastic work deformations. Temperature profile and energy dissipation history of the FE model have been analyzed. The peak temperature at the tip of the pin and frictional dissipation energy are in close agreement with the experimental work done by Gerlich et al. 1, which is about 5.1% different. © 2010 Taylor & Francis Group, LLC.