Why do some rebel groups fragment while others do not? Existing research has demonstrated that variation in rebel fragmentation can partly be explained by the violent socialisation methods the groups employ. One such method is sexual violence (Cohen 2016), which can increase unit cohesion but do so to a point that it results in rebel group fragmentation (Nagel and Doctor 2020). However, the effects of non-violent socialisation methods on rebel fragmentation are not examined in the current literature. I argue that non-violent socialisation through political education and indoctrination leads to a similarly strong bond as does violent socialisation. Moreover, I contend that the choice between violent and non-violent socialisation is determined by the social resources (ideology, religious beliefs, or ethnic affiliations) the group possesses and that education and indoctrination campaigns are likely to be funded through natural resource extraction. Both claims are tested with new and originally collected data on the socialisation efforts of rebel groups that compass a global sample at the conflict-year level. Ultimately, the theoretical model and results I present can help us forecast rebel fragmentation as well as when violence against civilians is to be expected and when not.