Abstract: Spontaneous volunteers have always been a relevant factor in disaster management. Digitalization and modern technologies such as social media and mobile devices had a great impact on the quality of spontaneous volunteer engagement and their mobilization. However, their targeted integration into official disaster management measures remains often challenging. In the last decade, there were different scientific and practical approaches to develop information systems for coordination of spontaneous volunteers addressing different scopes and scenarios. In this article, we have analyzed the current state of the art and use a methodological approach to develop a taxonomy for classifying existing and emerging developments in the field. The taxonomy is intended to assist practitioners in selecting appropriate systems for their respective purposes as well as support researchers in identifying research gaps. The resulting research artifact has undergone an initial evaluation and can support maintaining a better overview in a growing subject area.