The aim of this chapter is to explore drivers of change in policies for persons with intellectual disabilities in one of the Nordic countries, Norway, from 1960 (when total institutions became questioned) to 2020. It is an empirical analysis based on policy documents, guided by theoretical ideas from “new institutionalism”. The chapter analyses the development leading to full deinstitutionalisation, and also the post reform developments. The main message is that changing ideologies are important but not sufficient. A favourable policy context is also necessary. In the 1980s and 90 s, deinstitutionalisation was supported by a general decentralisation of welfare services, whereas later contextual developments appear to be a barrier to the realisation of the ideals of the 1990s. Services are currently the responsibility of local authorities. They experience severe fiscal strain and have introduced a set of new management principles. It is argued that this produces a context where policy goals for marginalised groups are more easily neglected. It is discussed what can currently be learned from an understanding of drivers of change in Norway, both beyond the Norwegian setting and for future developments.