A number of trends have recently emerged in the areas of environmental building designs and high-performance systems. However, in spite of many design and technical efforts to improve the performance using multiple building enclosure components, especially green roofs, the critical uncertainty of existing mechanisms, such as pre-defined computational modeling and design guidelines, has frequently resulted in lower building performance efficiency than intended by the design. In reality, examination of many actual green roof performance cases revealed an even larger energy usage and/or lower environmental performance of the building, where implemented, than those of the adopted base cases. To address this challenge, we developed a Climate-Responsive Evidence-Based Green-Roof Design Decision Model that uses finely tuned performance modeling with calibration by actual measured data from existing best practices. By utilizing these composite best-practice cases as a source for reference data, this project can provide stakeholders (e.g., architects, facility managers, building / roof engineers, owners, etc.) with readily applicable and reliable green roof design solutions for new / renovation projects. A design solution algorithm that was developed by this project adopted statistical tools and performance simulation modeling. This project approach can lead to effective green roof design decisions in an early stage of an individualized project with various climate and geometric conditions, based on integrated principles of design and building architectural configurations.