In Australia, there is an increasing interest in using extensive green roofs to make buildings more sustainable and provide a number of social, ecological, aesthetic and thermal benefits to cities. The potential of green roofs to reduce building energy consumption has been extensively studied overseas in a variety of different climates. However, in Australia the green roof industry is relatively new. There is still very little information on the thermal properties of Australian green roofs and their performance. Further, as a relatively new industry, there is a general lack of specific policies and initiatives to promote green roofs. In this paper, the authors briefly review the research investigating green roof thermal performance in various climates and analyse policies and actions that have been implemented internationally to foster green roofs with an emphasis on their thermal performance. The results showed that most policies were focused on ecological benefits, such as stormwater runoff reduction, rather than thermal benefits. Many green roof policies had difficulty interpreting the thermal performance of green roofs, because of the dynamic nature of green roof R-values. In this study, the effectiveness of overseas green roof policy is discussed and recommendations how they could be adapted for Australian cities are provided.