In this paper, we investigated the reason(s) why natural ventilation is not as popular as air-conditioned or mixed-mode ventilation systems in Green-rated office buildings in New Zealand. To achieve this, we had three objectives. Firstly, we reviewed the Green Star criteria for thermal comfort in office buildings to ascertain which ventilation system the NZ Green Star rating tool promotes. Secondly, we ascertained the perception of occupants in office buildings regarding thermal comfort. This was followed by an interview with building experts regarding factors that affect the use of natural ventilation in New Zealand offices. The findings showed that the NZ Green Star thermal comfort criteria encourage the use of mechanical ventilation over natural ventilation which results in designers opting for air conditioning systems in office designs. We observed that occupants of naturally ventilated spaces were least satisfied with the thermal comfort of their offices when compared with occupants of mixed-mode and air-conditioned offices. This study fulfils the need to encourage the use of natural ventilation in office environments by designers and building owners. Further study on other aspects of the indoor environment quality that is related to naturally ventilated systems such as lighting and noise is required in a bid to ascertain its viability in office environments.