Although interest in implementing trees on buildings has increased over the last few years, there is limited literature and policies to guide design and implementation. This lack of evidence and guidelines hinders the implementation and increases the risk of failure and maintenance costs. This study seeks to address this by investigating the design requirements of trees on buildings based on the best practice experience of worldwide experts using survey and interview techniques. This study is novel in that it introduces a complete design framework for trees on buildings that can be used to enhance future designs and implementation. The design framework consists of four stages: preparation, critical analysis and studies, techniques and design elements, and construction and maintenance plans. This design framework serves to guide designers, developers, and policymakers to make better decisions regarding trees on buildings. This paper also highlights areas where existing policies and literature need to be improved to further enhance the design framework, broaden the knowledge regarding trees on buildings, and reduce the challenges to their implementation.