Suicide is a global challenge. Although it is clear that socioeconomic and demographic factors influence suicide rates, we know little about the impacts of the built environment on suicide rates. Methods: We investigated the relationship between characteristics of the built environment and suicide death rates over a 13-year period in 151 rent-only public housing communities in Hong Kong. The regulations of the public housing authority in Hong Kong constituted a natural experiment with minimal self-selection bias. We conducted hierarchical regression analyses and found that characteristics of the built environment were significantly associated with suicide rates after controlling for SES and demographic factors at the community level. Results: Three significant environmental factors were identified distance to the nearest urban center, distance to the nearest Mass Transit Railway station, and gross flat area per person. Conclusion: These findings demonstrate a significant association between features of the built environment and suicide rates. They also suggest possible interventions that might reduce suicide through design, or redesign, of the built environment. Lastly, we propose an environmental theory of suicide based on the Interpersonal Theory of Suicide.