Purpose - The aim of this article is to describe and analyze a case of interorganizational and intersectoral collaboration on workplace health promotion involving nine municipalities in a Swedish region. Design/methodology/approach - A holistic case study design was chosen. The work of a project group responsible for developing plans for collaboration in the target area of health promoting leadership was studied. Observations at project meetings, interviews with project members, and written project documents were analyzed by qualitative methods. Findings - Collaboration on health promoting leadership was seen as a strategy to reduce the sickness rate among the employees in the municipalities. The best way to develop such leadership was considered to be through supporting good leadership in general and improving the general working conditions of managers in the municipalities. Moreover, it was regarded as a critical condition to have structural arrangements and resources to continue this collaboration. Practical implications - An implication of the study is that collaboration on workplace health promotion should be organized initially on a small scale, giving time and opportunities for the participants to develop mutual trust with one another. It is also important to involve participants with different knowledge and experiences in the field. Thus, it may be possible to develop strategies for health-promoting leadership contributing to the overall aim of a decreased sickness rate. Originality/value - There is limited research on barriers and facilitating factors for interorganizational and intersectoral collaboration on workplace health promotion. This study contributes an analysis of important conditions for this kind of collaboration.