Petilla de Aragón is a town and municipality in the autonomous community of Navarra, in northern Spain. Despite its name, it lies within Navarra rather than Aragón.
The municipality is notable for being formed by two enclaves, Petilla de Aragón itself and Los Bastanes, which are entirely surrounded by the neighbouring autonomous community of Aragón. This makes it a piece of Navarra separated from the rest of the community by Aragonese territory.