The authors used a dynamic systems theoretical approach to examine intraindividual variability in emotional responses during the transitional period of adolescence. Longitudinal diary data were collected regarding conflicts between 17 teenage girls and their mothers over a period of a year. The results revealed a reversed u-shaped relation between girls' emotional variability and the number of conflicts. Moreover, girls who showed limited variability in emotional states across conflict episodes tended to attach the same emotional state to divergent conflict topics. Explained as the result of a self-organizing process, emotional rigidity (i.e., a lack of variability and contextual sensitivity) possibly undermines the adaptive potential of the parent-adolescent system in times of relational transitions and developmental changes. (Contains 3 figures, 5 tables and 7 footnotes.)