Given the bidirectional association between psychopathology and relationship distress, an in-depth understanding of couples' interaction processes that contribute to psychopathology is needed. This study examined the interpersonal dynamics of vocally-encoded emotional arousal (fundamental frequency, f0) during couple conversations and their associations with depressive symptoms, anxiety symptoms, and relationship distress. Data from eight samples were pooled (N = 404 couples) to examine (a) overall trajectories of f0 across the interaction and (b) moment-by-moment intraindividual changes in and interpersonal reactivity to partners' f0. Multilevel growth models and repeated-measures actor-partner interdependence models demonstrated that individuals with more severe depression showed more synchronizing reactivity to their partners' f0 on a moment-by-moment basis, and their overall baseline level of f0 was lower. More severe relationship distress was associated with more steeply increasing trajectories of f0 and with greater synchronizing reactivity to partners' f0. Relative differences in depressive symptoms between the two members of a couple were associated with interpersonal dynamics of f0 as well. There were no associations with anxiety symptoms. Thus, depressive symptoms were associated with characteristic interpersonal dynamics of vocally-encoded emotional arousal; yet, most consistent associations emerged for relationship distress, which future studies on individual psychopathology should take into account.