Although research on bystander intervention and informal social control of intimate partner violence (IPV) is increasingly common, empirical anomalies remain and experimental studies on population samples are rare. This study reports the effects of a new experimental approach to the study of informal social control of IPV by neighbors on a small population sample of 100 married men in Seoul, South Korea. We hypothesized that men randomly assigned to a high‐perceived informal social control condition would have lower self‐estimated likelihoods of IPV perpetration in response to a vignette. We also hypothesized that the effect of random assignment would be different for that portion of the sample that reported perpetration of family violence (IPV or child abuse). Compared to the nonperpetrating portion of the sample, perpetrators of family violence in the sample randomly assigned to the high perceived control condition experienced a significant drop in self‐estimated likelihood of IPV perpetration.