This empirical study predicts and finds that effectiveness of ad humor is jointly determined by the humor process (i.e., incongruity resolution and arousal safety) employed in the ad and the cultural orientation (i.e., uncertainty avoidance and individualism-collectivism) of the ad viewer. In particular, attitudinal effects elicited by the cognitive/affective uncertainty elements in ad humor are more pronounced among consumers who have higher uncertainty avoidance, as well as among those with more collectivistic orientations. The theoretical and managerial implications stemming from the cultural boundaries of ad humor are considered. Research avenues suggested by the findings are also discussed.