In this article, language policy is analysed in relation to multilingual practices in primary school through an understanding of the policy on different levels--as management, perception and practice. The article is based on longitudinal ethnographic action research that was conducted parallel to local school development. Here we draw on material from observations, interviews and notes written by participating teachers when arguing that engaging with policy processes may constitute a powerful tool for school development. In this case, development of language policies that include students' diverse linguistic backgrounds, supported students in their language development in the bridging between L2-support and work in the mainstream classroom. The conclusion is that the promotion of language policies that oppose hierarchies of power is crucial in terms of social change as it promotes social equity and fosters change. Involvement in terms of policy processes may shift the boundaries for what is possible in education and may thus constitute a powerful tool in school development.