Parental burnout refers to loss of energy and pleasure in the parental role. It is predictive of psychopathological outcomes in parents and dysfunctional parenting behaviors. Support of parental duties is central to alleviation of parental burden and prevention of burnout. Coparenting is the concept related to interparental mutual support in rearing a child. However, the links between coparenting and parental burnout have yet to be assessed. We thus aimed in this study to assess which dimensions of coparenting are linked with parental burnout. A total of 306 participants from the French-speaking part of Switzerland (120 fathers, 186 mothers) completed online questionnaires about parental burnout, their coparental relationship, and sociodemographic characteristics. We performed hierarchical regressions, entering sociodemographic characteristics in a first block and coparenting dimensions in a second block. Results showed that (i) a higher number of children and having younger children are linked to higher burnout; (ii) coparenting exposure to conflict is related to higher burnout, whereas endorsement of the partner's parenting is related to lower burnout; and (iii) no interaction effect occurs between sociodemographic characteristics and coparenting variables. Coparenting thus significantly contributes to the occurrence of burnout syndrome. Working on the coparental relationship preventively in parental educational programs or at a relational systemic level in therapy may help prevent burnout. Treating one parent only may not be sufficient to alleviate burnout, as negative coparenting could counter the effect of individual therapy.