ABSTRACTSustainability incidents (e.g., human rights violations, pollution, bribery, etc.) in supply chains continue to manifest globally. Yet, evidence from practice shows such incidents tend to recur within the same supply chains despite stakeholder attention. We investigate the manifestations of supplier sustainability incidents (SSIs) and purchasing managers' reaction to them over time, looking for traces of the slippery slope effect. We also test whether moral disengagement and psychological distance can further impact decisions toward SSIs. Through a series of experiments on both social and environmental SSIs and a follow‐up qualitative study (683 participants in total), we find evidence for the impact of moral disengagement and psychological distance on purchasing managers' reaction to SSIs. However, results for the slippery slope effect were mixed. Our supplementary qualitative study found evidence for the slippery slope effect, as well as moral licensing/cleansing and moral psychology.