Food safety and food security are two important public health sectors within Canada, which aim to address foodborne disease and food insecurity, respectively. While these sectors are often siloed within public health organizations, the actions of the two sectors often interact and conflict at the program level despite their common goal of improving population health. The objective of the present study was to identify determinants that influenced the success of collaboration between practitioners of the two sectors in British Columbia, to inform Canadian food policy. We inductively analyzed 14 interviews with practitioners working in the two sectors who had experience with successful collaboration. Data were interpreted in consultation with an inter-professional collaboration framework. Participants identified determinants at the systemic level, including the cultural, professional, educational, legislative, and political systems, which were often considered barriers to collaboration. Participants also identified determinants at the organizational level that influenced the success of collaboration between the sectors, including: the organization’s structure and philosophy, leadership, resources, and communication mechanisms. Finally, participants identified interactional determinants as ways to overcome existing barriers, including: willingness to collaborate, trust, communication, mutual respect, and taking a solutions-oriented approach. Practitioners working in food safety and food security can apply the interactional determinants identified in this study to mitigate existing barriers to collaboration and support more synergistic food policies.