Social sanctions can be effective for sustaining beneficial norms by harnessing the power of social pressure and peer monitoring. Yet, field evidence regarding how norms might be linked to perceived risk of sanction is limited. In this study, we focused on communities located in peri-urban areas of Tamil Nadu, India, and examined how people's perceived prevalence of a socially desirable behavior (i.e., toilet use) relates to the perceived risk of sanctions for deviating from this behavior (i.e., open defecation) in the sanitation domain. Cross-sectional data from 2427 participants in 75 communities revealed that the majority (77%, n = 1861) perceived the risk of informal sanctions related to open defecation. Among those, verbal reprimand was the most common (60%), followed by advice (30%) and gossip (7%). Results from multilevel logistic regression indicated that those who believed toilet use was prevalent in their community were more likely to perceive the risk of social sanctions for open defecation. Moderation analysis revealed that this relationship was robust among women, but attenuated among men. Our findings suggest that women are more likely to expect social sanctions if they deviate from what is perceived as the prevalent sanitation behavior (e.g., toilet use) in their community. Open defecation practices are known to cause psychosocial stress among women due to their experiences with sanitation insecurity, which may include fear of disapproval from community members. Our results highlight the need for gendered intervention strategies when sanitation programs leverage social influence for behavior change.