This research investigates the thermal performance of a green roof in Ottawa, Canada. In chapter 1, the measured thermal performance of the green roof is defined as the percent reduction in total monthly heat exchange promoted by the green roof, relative to a conventional roof. Thermal performance ranged between 31.0 - 62.8% between May and September in 2016 and 2017, with reduced performance in the shoulder and winter seasons. In chapter 2, a resistor-capacitor (RC) and implicit finite difference (FD) model are developed, calibrated, and validated over the same period and are used to predict hourly rates of heat flux and thermal performance. Predicted heat flux exhibited a root-mean-square-error between 0.51 - 1.0 W/m2 and 0.41 - 0.81 W/m2 for the RC and FD models, respectively, in 2016.