In recent years, researchers have addressed the issue of urban freight transport through diverse methods, garnering significant attention in the literature. In this research, we propose a new composite indicator to assess the sustainability of urban freight transport. Due the lack of data and the imprecision in information, we employ a fuzzy logic based methodology to calculate the composite indicator. The main novelty of this study consists in assessing urban freight transport by considering five sustainability dimensions (economic, environmental, social, political and spatial), and relying on short- and medium-term decisions. We apply the presented approach in the city of Sfax, Tunisia, to assess the current sustainability status of urban freight transport. The resulting analysis provides the decision-maker with more comprehensive information for enhancing sustainability decisions and identifies the associated barriers. We identified eleven least sustainable indicators.