Social workers’ policy engagement has been the subject of growing interest in the social work discourse in recent years. In order to contribute to theoretical and empirical knowledge for social workers and social work organizations seeking to undertake their policy role, this article will seek to better understand one of the types of factors that determines this engagement, particularly on the macro level. The focus of much of the discussion on the factors associated with social workers’ policy engagement has been on social workers’ motivation to engage in policy practice and the degree to which their workplaces facilitate this type of activity. However, the discourse tends to ignore the impact of the policy environment on this. Drawing on the concept of “opportunity structures” and insights from the neo-institutionalist literature, this article suggests that social workers’ access to the policy-making process is crucial if we seek to better understand their policy practice. On the basis of examples from different countries and historical periods, and a more in-depth examination of Israeli case studies, we underscore the ways in which opportunity structures deriving from institutional or temporal factors lead to divergences in the form and level that policy engagement by social workers takes in different contexts.