This dissertation analyzes and compares successful and unsuccessful trajectories of state formation in six states in Sub-Saharan Africa. My research has been primarily motivated by two observations: (i) the formation of states has generally been equated with Western statehood, and it has rarely been studied in a systematically theoretical way beyond this context; (ii) particularly in International Relations (IR), the discourse on states in the Global South has often been framed in terms of failure, thus making externally-led state-building an imperative. It is striking that this debate disregards the historical records of state formation (Chapter 1). For this reason, I have decided to shift the perspective by bringing a classical state formation perspective back in to analyze state-making in the Global South. To understand what makes state formation successful, I draw on, and re-engineer, theories of European state formation. I have isolated four mechanisms that are particularly significant for the emergence of statehood: warfare; social coalitions; the character of collective identities; and the mode to satisfy the revenue imperative — taxation or rents. Carefully weighing the explanatory power of the different mechanisms against each other, I define them as pathway mechanisms and intervening mechanisms and use them complementarily to identify pathways to successful state formation (Chapter 2). Based on this theoretical framework, I conduct several theory-guided pairwise case studies. Two of these paired comparisons consist of one relatively successful state formation and one failed state formation trajectory, and the last pair juxtaposes two cases which are inbetween success and failure but with sufficient variance regarding their degree of statehood to make a comparison worthwhile. All pairs have started from similar initial conditions. In total, I examine six attempts at state formation in three pairs: Somaliland/South-Central Somalia as of 1991; Namibia/Zimbabwe as of their respective dates of independence (1990/1980); and Ethiopia/Eritrea as of 1991 (Chapters 3-5). Having analyzed all cases, I transcend the pairwise perspective in the final chapter and revisit all six attempts at state formation. In particular, I compare the trajectories of those cases with a similar degree of success or failure to draw general conclusions on the pathways of successful and failing domestically-led state formation. Lastly, I address some questions raised by my current research in order to indicate avenues for further investigation.