A Health in All Policies approach requires creating and sustaining intersectoral partnerships for promoting population health. This scoping review of the international literature on partnership functioning provides a narrative synthesis of findings related to processes that support and inhibit health promotion partnership functioning. Searching a range of databases, the review includes 26 studies employing quantitative (n = 8), qualitative (n = 10) and mixed method (n = 8) designs examining partnership processes published from January 2007 to June 2015. Using the Bergen Model of Collaborative Functioning as a theoretical framework for analyzing the findings, nine core elements were identified that constitute positive partnership processes that can inform best practices: (i) develop a shared mission aligned to the partners' individual or institutional goals; (ii) include a broad range of participation from diverse partners and a balance of human and financial resources; (iii) incorporate leadership that inspires trust, confidence and inclusiveness; (iv) monitor how communication is perceived by partners and adjust accordingly; (v) balance formal and informal roles/structures depending upon mission; (vi) build trust between partners from the beginning and for the duration of the partnership; (vii) ensure balance between maintenance and production activities; (viii) consider the impact of political, economic, cultural, social and organizational contexts; and (ix) evaluate partnerships for continuous improvement. Future research is needed to examine the relationship between these processes and how they impact the longer-term outcomes of intersectoral partnerships.