Due to socio-political issues in Dutch society, citizenship education (CE) became obligatory by law in the Netherlands in 2006. Schools were to decide on their local CE curriculum. This contribution intends to open up the black box of school-based curriculum-making efforts for CE. It reports on a four-year study in four schools for secondary education. In each school, teachers designed (parts of) their CE curriculum with guidance during weekly coaching sessions. The central question is, what are the professional experiences and results of teachers who are involved in guided school-based CE curriculum-making? The qualitative data set comprised of interview and focus group data as well as artefacts such as CE-activities designed by teachers. Findings show teachers' preference for broad and integrated approaches to CE, and that teachers needed guidance not only to improve their CE-knowledge and design abilities, but also to increase their socio-political skills for school-wide implementation. These results are discussed in view of the current tendency in the Netherlands to define CE in a more centralised and content-specific manner and in doing so limiting the space for teachers as curriculum-makers.