Food security is a hugely important and complex issue. Such complexity is demonstrated, inter alia, by the lack of a consistent definition of food security under the international policy framework. Of the various elements that can affect food security, trade in agriculture plays a significant role both in positive and negative terms. This article considers the concept of food security as emerging from the WTO Agreement on Agriculture (AoA) and discusses it in the light of the most commonly accepted definition of food security (i.e. the FAO’s definition). The analysis highlights a bifurcation in the concept at stake, depending on the forum considered. According to the AoA, food security is conceived as an exception. It does not consider the individual condition, but focuses either on a country’s agricultural self-sufficiency or on the suitability of food self-reliance at national and global levels. While within the UN agencies, a multifaceted and multidimensional concept emerges.