AbstractMultimodal transportation serves diverse needs and enhances the efficiency and fairness in travel. Despite the increased demands in multimodal transportation development, there lacks a comprehensive framework and associated quantitative methodology to assess the level of diversity of a multimodal transportation system. To this end, the objective of this study is to develop a comprehensive framework to assess the diversity of a multimodal transportation system from both physical infrastructure perspective and travel behavior perspective. From the physical infrastructure perspective, the functional richness and evenness of each transportation mode in an area are calculated and aggregated into one diversity measurement using the entropy weight method. From the travel behavior perspective, the diversity of travelers’ behaviors in an area is quantified based on the number of trips made by each mode using the entropy method. The proposed framework was implemented in a case study of the city of Hartford, CT. The physical infrastructure diversity and travel behavior diversity of multimodal transportation systems in six zip code areas of Hartford were calculated and compared. The case study results showed that the physical infrastructure diversity and travel behavior diversity revealed similar trends in most areas in the case study, with some exceptions which could potentially be explained by sociodemographic factors of different areas. The proposed framework could help transportation planners and decision-makers in obtaining a holistic understanding of the diversity level of a multimodal transportation system, considering urban planning strategies to enhance diversity in travel.