Abstract. Theories of coalition formation represent a diverse set of arguments about why some government coalitions form while others do not. In this article, the authors present a systematic empirical test of the relative importance of the various arguments. The test is designed to avoid a circularity problem present in many coalition studies – namely that the theories are tested on data of national government coalitions in postwar Europe: the very data that gave rise to the theories in the first place. Instead, the authors focus on government coalitions at the municipal level. They base their analysis on an expert survey of almost 3,000 local councillors from all municipalities in Denmark. They use conditional logit analysis to model government formation as a discrete choice between all potential governments. The analysis confirms some, but far from all, traditional explanations such as those based on office and policy motives. At the same time, the analysis raises the question of whether actors really seek minimal coalitions.