Student dormitory advisors (n = 16) made trait/situation attributiohS to themselves and also identified three friends and three acquaintances. Friends (n = 41) and acquaintances (n = 43) then made attributions to themselves alodg with attributions and familiarity ratings of the advisors who identified them. The actor-observer effect was obtained for situational but not for trait attributions, both when advisors' self-attributions were compared to attributions made about them by friends and acquaintances (common target) and when the latter's self-attributions were compared to their target attributions (common rater). Among friends and acquaintances, target familiarity was positively related to trait attributions and was negatively related to uncertainty attributions. Also, familiarity was positively related to the validity of situational but not of trait attributions. It was concluded that familiarity appears to influence the process of attribution, but differentially for dispositional vs. situational attributions and for actor-observer differences vs. observer variations in attributions. Moreover, increased information about the actor as a result of greater familiarity may lead to both more accurate and more favorable attributions.Over a decade ago, Jones and Nisbett (1972) hypothesized that actors tend to attribute their actions to situational causes whereas observers tend to attribute the same actions to personal dispositions. Several studies, using different methodologies, have supported this basic actor-observer hypothesis. Some studies have asked subjects to make trait ascriptions for self and others. For example, Nisbett,