There are thousands of school gardens in the United States, and there is anecdotal evidence that school garden programs can enhance students' learning in academic, social, and health-related domains. There has been little rigorous research, however, on the effects of school gardens or on the factors that promote the sustainability of these programs. This review draws on ecological theory to conceptualize school gardens as systemic interventions with the potential for promoting the health and well-being of individual students in multiple interdependent domains and for strengthening the school environment as a setting for positive youth development. This review (a) summarizes the small literature regarding the impact of school garden curricula on student or school functioning, (b) provides a conceptual framework to guide future inquiry, (c) discusses implications of this conceptualization for practice, and (d) suggests further research needed to better inform practice. (Contains 1 figure.)