Positivity resonance, defined as a co-experienced kind-hearted positive emotion, is commonly observed to strengthen relationships in the United States. However, it is unclear whether levels of positivity resonance differ across cultures. Prior research suggests that in cultures that are perceived as offering more freedom and choice in social ties (defined as high relational mobility cultures), individuals more frequently engage in adaptive strategies to build relationships. We hypothesized that positivity resonance, achieved via such adaptive strategies, might be similarly linked to cultural variation in relational mobility. Across two studies (N = 5,711) we found supportive evidence for our prediction that, compared with European American participants, East Asian participants showed lower levels of positivity resonance with strong social ties. Such differences were in part explained by lower levels of perceived relational mobility among East Asian participants. Comparable effects were not present for weak social ties. Implications for theories of culture and emotion are discussed.