Professor Liam O’Brien was the keynote speaker at eSim 2018 Conference in Montreal in May. His topic was Simulating Occupants in Buildings. To represent the effect of occupants on building performance, occupant models can be implemented in BPS tools.O’Brien’s workshop covered the fundamentals of occupant behavior modeling and implementation in BPS tools. The procedures for implementing occupant models in EnergyPlus and OpenStudio softwares was demonstrated.