About the Study Green Building Rating Systems (GBRSs) play a key role in assessing environmental impact and sustainability, and in facilitating decarbonisation in the building sector.[dt_gap height="10" /] Eight GBRSs were chosen for this comparative study: CGBL, BEAM Plus, BREEAM, Green Mark, Green Star, LEED, EDGE, and NABERS Energy. They are categorised into two main types: scoring-based rating systems and performance-based rating systems, based on their certification methodologies. Of these, BEAM Plus is a Hong Kong-based GBRS and the others are from other jurisdictions.[dt_gap height="10" /] This study compares the similarities and differences between the GBRSs, in particular taking a.