BACKGROUND AND AIM: Urban agriculture may benefit the health of those who practice it by encouraging healthier habits such as increased consumption of fruit and vegetables, physical activity, exposure to green spaces, and social interaction. These habits may also act synergistically to improve health above and beyond that expected if the impacts of these habits were additive. The pathways by which urban agriculture may impact health and any potential synergies between healthy behaviours remains under-explored. METHODS: A literature review informed the development of a conceptual model describing mechanisms by which urban agriculture has the potential to improve population health. A survey of 625 UK urban horticulturalists was undertaken to compare participants’ healthy behaviours and health status with the general urban population represented by UK’s large UK Biobank cohort (N∼500,000). The cohort was additionally used to evaluate interactions between healthy behaviours and any synergistic effects of these on health markers. RESULTS: Urban horticulturalists were found to display healthier behaviours (fruit and vegetable intake, physical activity, and time outdoors (or greenspace exposure) than the general UK population sample. However, this was not necessarily reflected in health markers (Bodymass index (BMI), medication use, loneliness, happiness, and self-health assessment). In contrast, evidence for synergies between healthy behaviours was found and these relationships are complex. Individually, the lifestyle behaviours: fruit and vegetable intake and physical activity positively correlate with health markers, but greenspace exposure does not. The interaction between fruit and vegetable intake and physical activity is also associated with good health markers. Still, when greenspace exposure is included, the associations are lost or, in some cases, are negatively associated. I showed that interactions between healthy behaviours are not simple with respect to synergistic effects: the relationships are not constant and vary depending on the level or state of the interacting lifestyle behaviours. CONCLUSION: Urban agriculture has a clear potential to improve different health behaviours, and furthermore, these behaviours may act synergistically to either the further improvement of, or detriment to, health. With logical and systematic planning, urban agriculture can thus be seen as an effective and efficient approach to improve urban living and the health of urban populations in developed countries.