Although there is evidence that green space influences mental health and well-being, there is little existing work delineating the specific characteristics or features of green space as it relates to mental health impacts. A starting point towards this goal is to uncover and better understand the mediating and moderating factors that influence the relationship between green space and mental health. The theoretical framework presented in this paper synthesizes information that was gathered through a scoping review of reviews designed to understand the aspects of green space that affect mental health and well-being.