The human dimension of building performance simulation can be approached from different vantage points. This contribution addresses the following three. First, building simulation tools and environments need to exhibit a high degree of usability. They are expected to provide effective support for generating building models and processing simulation results. Second, the representation of people's presence and actions in building simulation models requires a sound empirical basis. It must be properly gauged toward applicable objectives of the modeling activity. Third, the human dimension is central to a large and important class of building performance indicators. These indicators are expected to properly capture the indoor environmental quality of built spaces in view of their suitability for human users.