The promotion of democracy has become a key objective of the European Union (EU) in sub-Saharan Africa.One of the ways in which this objective is pursued is by reacting to violations of democratic principles using negative measures: naming and shaming strategies or economic/diplomatic sanctions. Yet the application of negative measures has been criticised as being characterised by "double standards", meaning that similar violations of democratic principles have led to a different response from the EU. This dissertation searches for explanations for these double standards. In-depth comparative studies on the motivations for double standards in the application of negative measures in sub-Saharan Africa in the post-2000 period have been lacking. While double standards have mostly been attributed to the prevalence of self-interested objectives of the EU, this dissertation considers two additional factors: (1) a potential conflict in the EU"s normative objectives (democracy, development and stability) and (2) expectations about the effectiveness of negative measures.These three explanatory factors (norms, self-interest and effectiveness) are investigated for ten case studies in sub-Saharan Africa: Eritrea, Ethiopia, Kenya, Chad, Niger, Nigeria, Rwanda, Guinea, Côte d"Ivoire and Zimbabwe. It is shown that there have been double standards in the EU"s reaction to violations of democratic principles in these countries: similar violations of democratic principles have led to different reactions from the EU (positive measures, low-cost negative measures and sanctions). The motivations for these double standards are then investigated by studying the potential impact of norms, self-interest and effectiveness.On the one hand, previous studies emphasising self-interest are confirmed. Historical interests related to the desire of member states to maintain their sphere of influence have in some cases led to double standards (Chad, Côte d"Ivoire, Zimbabwe). Moreover, the growing concern for self-interested security objectives such as the war on terror has led to increased tolerance for governments that are seen as crucial allies in fighting these security concerns (Ethiopia, Nigeria, Chad), while sanctions were more easily adopted where this was not the case (Zimbabwe, Guinea, Côte d"Ivoire). On the other hand, the study also found evidence that runs counter to the importance of self-interest: (1) commercial interests were found to have little explanatory value, (2) some countries that can also be considered allies in the security sphere were not shielded from negative measures (Kenya), and (3) the EU also avoided negatives measures in countries that were not allies in the pursuit of security objectives (Eritrea, Rwanda). Furthermore, the EU"s other normative objectives (stability, development) were found to be equally important. Negative measures were more easily adopted in countries where development performance had been weak (Zimbabwe, Guinea, Côte d"Ivoire, Niger) or where internal stability was under threat (Kenya, C...