This paper explores comparatively and historically why Nordic and Continental welfare and education regimes differ in the degree of comprehensiveness of their primary and lower secondary school systems. It analyses how school reforms, reform attempts and coalitions in the post-war decades were shaped by different cleavage structures in Norway and the German federal state of North Rhine-Westphalia. While the class cleavage was most dominant in school politics in both cases, rural-urban, centre-periphery, state-church and communist-socialist cleavages shaped party systems, political alliances and outcomes decisively. In particular, the rural population was integrated into different cross-interest coalitions: in Norway, its political representatives consented to social democratic comprehensive school reforms, while in Germany, they opposed such reforms. This was related to cross-cutting conflicts concerning centralisation and language in the Norwegian case and regarding religion, centralisation and (anti-)communism in the German case.