This paper undertakes an international comparison of globalsustainability tools and examines their characteristics and differences.Most importantly, it focuses on which tools from different countries canbe directly compared with each other (i.e., is a five-star building withone rating system directly comparable with a four-star rating of anotherrating system?). The results are designed to provide some clarificationof the assessment tools for sustainable buildings, which in turn willassist investors, developers, tenants, and government bodies in makinginformed decisions about green buildings. In addition, it is envisagedthat removing some of the uncertainty associated with sustainablebuildings will increase transparency for stakeholders and facilitate theiracceptance.