Personality psychology has long recognized the importance of situations for determining behavior, but little research has directly examined the degree to which the cross-situational consistency of behavior is associated with the similarity of situations. In two studies, participants (n=138 & 116) engaged in several dyadic interactions, and their behavior was coded from a videotaped record. Behavioral consistency was examined in terms of single behaviors and person-centered behavioral profiles. Addressing subjective situational similarity, Study 1 showed that participants who rated the two situations as relatively similar were relatively consistent in their behavior across the situations. Addressing objective situational similarity, defined as the degree to which situations shared common elements, Study 2 showed that participants were more behaviorally consistent across similar pairs of situations than across dissimilar pairs. In addition, Study 2 found that behaviors that are relatively automatic and impulsive were more consistent than behaviors that are more controlled and cognitively mediated. Regardless of how situational similarity or behavioral consistency were operationalized, greater similarity was related to greater consistency.