In Study 1, 7-month-old infants (N = 58) looked reliably more at an adult's face when she playfully pulled a toy away from them compared with when she simply handed them the toy. In Study 2, 7- and 9-month-old infants (N = 36) interacted with an adult who played a teasing game and then held a neutral or happy facial expression. Compared with a baseline in which infants looked equally to both expressions, after the tease, infants looked longer at the neutral compared with the happy expression. By 7 months, infants may use facial expressions to disambiguate others' actions.