Energy access, as defined in SDG 7, is a consistent component of decent livelihood and is therefore strictly connected to the fulfillment of the broad goal of sustainable development. While it may have significant impacts on various dimensions of development and sustainability, this study focuses on its effect on the level of food security of the overall population (SDG 2). Although there are many reasons to suppose that electricity access is positively related to food security, such impacts are expected to accrue through both immediate and income-mediated routes whose size and prevalence are unknown. The immediate impacts of electricity access on food security refer to the effects on food production (availability) and on food conservation and preparation (utilization). Income-mediated impacts include cross-sectoral productivity increases and the creation of new economic activities, generating new income that, in turn, would improve the economic access to food. After theoretically discussing the two kinds of impacts, this work empirically verifies how the prevalence of undernourishment (SDG indicator 2.1.1) is related to the percentage of population with access to electricity (SDG indicator 7.1.1) in a panel of 54 developing countries over the period 2000–2014. By adopting a multi-step estimation method, we disentangle the immediate effects of electricity access on food security from the income-mediated effects that stem from changes in GDP per capita and its distribution. Results show that electricity access mainly exerts immediate impacts on food availability and utilization, with only one fifth of impacts coming from income-mediated effects. This finding may lead policy-makers to prioritize off-grid electricity investments in proximity of vulnerable households through small-scale and household-level electricity systems, which may improve food security by immediately affecting the local and subsistence food production, conservation and preparation.