Although parents' parenting stress has been found to be related to coparenting, existing research has mostly focused only on one parent or examined the unidirectional effects between the two factors. The present study investigated the actor and partner effects as well as the bidirectional association between parents' parenting stress and coparenting in Chinese society. The study participants were 522 Chinese father−mother dyads with elementary school‐aged children who followed for two measurement occasions (half a year apart). The cross‐lagged actor‐partner interdependence model (APIM) was used to examine the actor effects and partner effects in the bidirectional associations between both parents' parenting stress and coparenting. The findings revealed that both fathers' and mothers' parenting stress significantly negatively predicted their spouses' coparenting (partner effects), and mothers' coparenting significantly negatively predicted their spouses' parenting stress (partner effects). However, the actor effects between parents' parenting stress and coparenting were not significant. Furthermore, there were significant bidirectional associations between fathers' parenting stress and mothers' coparenting. Findings from the present study reveal the dynamic interaction between parenting stress and coparenting. The results point to the need for providing preventive interventions to parents with high levels of parenting stress and establishing a collaborative interaction framework between parents.