Despite the third wave of democratization, dictatorships are still widespread global phenomena. However, in comparative research they are often treated merely as theoretical anomalies and empirical residual categories. By addressing this shortcoming, this research has three overall ambitions which are reached by reviewing, compiling and analyzing earlier research. First, different perspectives on how to define dictatorships are discussed. This makes it possible to approach the regimes in a more nuanced way compared with only classifying them as non-democratic. It is no understatement to claim that dictatorships are heterogeneous. Therefore, the second ambition of this research is to discuss different approaches to how to categorize these regimes more precisely. Theoretically valid categories are necessary when carrying out empirical inquiries. Third, and most absent in contemporary research, the ambition is to elaborate upon the factors that can explain dictatorships. In other words, what constitutes the explanans in an explanatory model of dictatorships and types of them? This includes both the existence of and transitions to dictatorship. To answer this question and to reach a theoretical framework for an explanation of dictatorship, contributions from a variety of research need to be put together. All in all, this paper will add greater theoretical understanding that is necessary for empirical examinations of dictatorships. Increased validity and increased confidence in explanations of dictatorships could be the result if the conclusions of this research are implemented in empirical studies.