There is a heated debate on whether markets erode social responsibility and moral behavior. However, it is a challenging task to identify and measure moral behavior in markets. Based on a theoretical model, we examine in an experiment the relation between trading volume, prices and moral behavior by setting up markets that either impose a negative externality on third parties or not. We find that moral behavior reveals itself in lower trading volume in markets with a negative externality, while prices mostly depend on the market structure. We further investigate individual characteristics that explain trading behavior in markets with negative externalities. Sutter M, Huber J, Kirchler M, Stefan M, Walzl M. Where to look for the morals in markets?. Exp Econ. 2020;23(1):30–52. doi:10.1007/s10683-019-09608-z This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Sections of the Abstract, Introduction, and Discussion and Conclusion are presented in the Podcast. Link to full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6991999/ Science Says is supported by Leksi (https://Leksi.co): the best education and study app to convert your notes, articles, or any document to audio so you can listen and learn no matter where you.