Interagency information sharing (IIS) has been identified as a powerful strategy to improve information and services in the public sector. In order to accomplish effective information sharing across organizational boundaries, the definition and clarity of roles and responsibilities are very important, particularly when the number and diversity of the agencies involved is high. However, there are very few studies that analyze the variables that affect this clarity in interagency information sharing efforts. Based on a review of current literature and a national survey conducted in the US, this paper quantitatively explores the determinants of clarity of roles and responsibilities. Consistent with existing literature, we found a significant and positive influence of diversity of participating organizations, the use of boundary objects, and communication skills on the use and emergence of need for clarity of roles and responsibilities in IIS project. Our findings open avenues for future research about the role of clarity of roles and responsibilities, its determinants, and other variables may play in mediating or directly explaining IIS success.