The social work profession has a long tradition of engaging with policy to promote social justice, to improve the well-being of service users and the working conditions of social workers. Previous studies have mainly focused on the levels and forms of social workers’ policy engagement. However, little is known about the factors that influence social workers’ decisions to engage in policy. Addressing this research gap, this study focuses on one very specific influencing factor that has so far only received limited scholarly attention, namely, political institutions. More specifically, the article draws upon Switzerland as a case study and examines how Switzerland’s direct democracy, federalist structure and consensus system promote social workers’ policy engagement. The findings illustrate how these three key political institutions provide important opportunities for social workers—as individuals or as members of groups and coalitions—to access formal and informal areas of the policy process, both as private citizens and as part of their jobs. Based on these findings, the final section of the article outlines suggestions for further research.