Microgrids are becoming popular in commercial buildings due to the recent drive to achieve net-zero energy targets and improve energy efficiency and reliability in building installations. The commercial building microgrids depict unique characteristics due to generation mix and various types of loads connected to the commercial building installations. Therefore, the commercial building microgrids require special consideration during the operation and control stages. Dynamic models of a microgrid enable researchers to investigate their operational performance and control techniques before the control schemes are actually being implemented in the microgrid system. It is essential to develop more accurate dynamic simulation models of a microgrid in order to verify the fidelity and the effectiveness of control schemes. This chapter presents a dynamic modelling of a commercial building microgrid system and conducts a stability analysis of the microgrid under various operating conditions.