OBJECTIVES: The relationships between local food environments and dietary patterns are important for older adults and could be different in men and women. We examined associations between exposure to neighbourhood food sources and food consumption and the moderating role of diet knowledge separately among older women and men living in Montreal in 2003–2005 (n = 722).METHODS: The proportion of fast-food outlets relative to all restaurants (%FFO) and the proportion of healthy food stores relative to all stores (%HFS) were estimated for 500 m buffers around participants’ homes. Two dietary patterns, designated ”Western” and ”prudent”, reflecting lower- and higher-quality diets respectively, were identified from food frequency questionnaire data. The unique and interactive effects of diet knowledge and food-source exposure on diet scores were tested with separate linear regression models for women and men.RESULTS: For men, greater %FFO exposure was related to lower prudent diet scores (β = −0.18, p = 0.02), but no effect of %HFS exposure was observed and no interactions were statistically significant. For women, an inverse relationship between %FFO and prudent diet scores was strongest among those with low diet knowledge (β = −0.22, p < 0.01). No other associations were statistically significant. CONCLUSION: Older men’s diet patterns may reflect unhealthy cues associated with fast-food outlets. Among women, diet knowledge potentiated both negative and positive relationships with the food environment. In the absence of consistent main effects of the food environment on diet scores, subgroup analysis is a promising avenue for research.