In this chapter, we report on the research findings from a school development project which took place in a large city in Germany over a period of 5 years. In 2013, the central educational authorities formed a public-private partnership with a foundation to start a development project that was inspired by school turnaround models in the US and included various interventions and efforts to support change in ten schools that were identified as ‘schools in difficult circumstances’. As such, the adapted school turnaround model serves as an example of introducing policies or models in school systems that have proven to be successful elsewhere. In this chapter, we present findings from our analysis of the changes taking place in the schools related to efforts and interventions to support the schools. Moreover, we discuss challenges regarding measurement of success according to the school turnaround logic and the need for more adaptive approaches for changing and developing schools in difficult circumstances - at least a long-term perspective on school development.