This article considers the way in which the likelihood of being observed by others affects a state’s conflict behavior. The analysis examines the effect of potential observation on the probability that a dispute will escalate to violence as well as the duration of war and peace. To analyze escalation, I employ the nonparametric local logit model, which frees estimation from restrictive functional form assumptions. The evidence suggests that outside observation can change states’ behaviors and that observers tend to modify their own actions based on what they learn. These results indicate that the typical assumption that international conflict is unobserved and unaffected by outside actors is empirically untenable.