Institutional education traditionally entails a premise of language separation. This article aims to analyse language management through spatial ideologies and practices as interconnected manifestations of language policies. Informed by post-structural theorisation, the analysis draws on ethnographic data produced at a co-located campus of Finnish- and Swedish-speaking monolingual schools in Finland and in a Sweden Finnish bilingual school in Sweden. In Finland, the two national languages, Finnish and Swedish, are separated in institutional education, although some of the monolingual Finnish- and Swedish-speaking schools share school facilities. In Sweden, education in one of the national minority languages, Finnish, is organised mainly in a few Sweden Finnish bilingual schools. The findings indicate that language separation in education is constructed as spatial ideologies and negotiated in the spatial practices of schools. Particularly in the context of Swedish in Finland, a spatial ideology promoting separation as a means for protecting language was reproduced. In Sweden, the protection of Finnish in the bilingual institution was under constant negotiation and embedded in the daily spatial practices rather than articulated as a spatial ideology. Linguistic hierarchies and their connections to national language policies become evident when analysing the spatial orders of educational institutions.