This research examined whether American and Chinese mothers' tendencies to base their worth on children's performance contributes to their affective responses to children's performance. Study 1 used daily interviews to assess mothers' warmth (vs. hostility) and children's school performance (N = 197; Mage = 12.81 years). In Study 2, such affect was observed in the laboratory following children's manipulated performance on cognitive problems (N = 128; Mage = 10.21 years). The more mothers based their worth on children's performance, the more their warmth (vs. hostility) decreased when children failed in Study 1. This pattern was evident only among Chinese mothers in Study 2. In both studies, child‐based worth did not contribute to mothers' affective responses to children's success.