Previous research has shown that clarity of roles and responsibilities (CRR) influences the performance of individual organizations as well as inter-organizational efforts. In the context of cross-boundary information sharing (CBIS), CRR has been found to enable other important determinants of success, such as building trust among members, increasing their willingness to participate, and mitigating some of their concerns about security, among others. However, few studies have attempted to understand the determinants of CRR in government CBIS initiatives. Sayogo, Gil-Garcia, and Cronemberger's (2016) analysis of results of a national survey identified three significant determinants of CRR in CBIS, (1) the extent participants use boundary objects, (2) participant skills in terms of collaboration, coordination, and communication, and (3) the diversity of the participating organizations and their goals. Seeking to expand on their findings in terms of new understanding about the influence of significant determinants of CRR in CBIS, this study draws on findings from eight U.S. state and local government public health and criminal justice CBIS cases. This study contributes to existing knowledge about CBIS in the public sector by characterizing the determinants and providing new understanding of the nature of the influence of the determinants of CRR on CBIS. In particular, it shows how the extent of boundary object use, collaboration, and the diversity of participants affect CBIS initiatives in different contexts. In practical terms, creating new understanding of the determinants of CRR has value for public managers and their leadership as they must increasingly collaborate and share information across the boundaries of organizations in the process solving increasingly complex public problems.