Urban shrinkage is a development path that has spread widely across Europe and worldwide. Shrinkage represents a challenge for urban planning and policy-making. Often, cities have lost population as reaction or response to extreme and unexpected events which will be understood as shocks in this paper. Modelling can help to better understand the relation between shock events and urban shrink-age as a response to them. Given this background, the purpose of this paper is a threefold one: Firstly, urban shrinkage is introduced and discussed as a response to shock events. Secondly, the functioning of urban shrinkage as a response to shock events is explained using the example of the postsocialist transition after 1989 and its effects on cities. Thirdly, processes and variables characterizing urban shrinkage are identified that might form a basis for modelling support for a better and more comprehensive understanding of its impacts. The explanatory power of the shock approach is, finally, critically reflected.