In recent years, African policymakers have embraced supermarket development as a form of food system modernization, but the impacts of the proximity of supermarkets on low-income households in a developing African city are largely unexplored. Using a sample of 680 households in seven of Accra’s poorer neighborhoods, we examine the dimensions and level of food security, household-level determinants, and what impact, if any, the arrival of supermarkets has had on local food security. Using two internationally accepted food-security metrics, (Food Consumption Score and Household Food Insecurity Access Scale), two economic measures (income equivalence and asset ownership), and satellite imagery of supermarket locations, we find that physical proximity to supermarkets is not significantly associated with household food security in low-income areas of Accra. The majority of poor households in Accra are currently food secure, but asset ownership is a much stronger predictor of food security than income. The relatively high degree of food security in Accra is likely related to credit-based relationships that households have with local food vendors. Further, given that supermarkets can compete with these so-called “informal” vendors for access to public space, these credit-based relationships will suffer with new supermarket development. Our study highlights the need for nuanced understanding regarding the role of consumer-retailer and retailer-retailer relationship in ensuring food access for low-income households in urban Africa.