This has been my PhD project which I completed in 2012 at the University of Nottingham. In my thesis, I examine the relationship between rebel organisation and violence against civilians in sub-Saharan Africa. I argue that rebels use such one-sided violence to enforce popular support when they are unable to secure support otherwise. An important determinant of this strategic use of violence is the rebels’ organisational configuration. Organisational factors such as the ideology of a rebel group, the occurrence of leadership divisions, the level of fractionalisation within a rebel group’s population base, the existence of external support and the number of competing rebel factions determine whether non-violent strategies to secure support are available or whether rebels can only rely on violent means to enforce support. I test this theoretical model using both quantitative and qualitative methods. I conduct a statistical cross-sectional study analysing the relationship between rebel organisation and rebel one-sided violence in sub-Sahara Africa between 1989 and 2007. I also use qualitative within-case analyses of the Sudan People’s Liberation Movement/Army (SPLM/A) and the Sudan Liberation Movement/Army (SLM/A) to test whether these correlations are actually driven by the causal pathways outlined in my theoretical model.