Research on the social dimension of plastics use, disposal and awareness is increasing. However, social research on microplastics perception is rare. While there are first exploratory surveys on how the public perceives microplastics (e.g. the Special Eurobarometer of the European Commission or the study of the German Federal Institute for Risk Assessment, BfR 2019) an in-depth study on the public risk perception of microplastics is still lacking. Thus, this paper takes up this research gap and explores the public risk perception of microplastics differentiated by socio-economic factors. The objectives of this article are (i) to investigate public risk perception and misconceptions of microplastics in order to inform future risk communication efforts on microplastics and (ii) to contribute to risk perception research of new and unknown risks. The paper is based on an online survey of 1.027 participants. The paper covers the following aspects: public knowledge about microplastics, public concerns about the effects of microplastics on the environment as well as on human health, perceptions on sources of microplastics and actions on microplastics.