[Correction Notice: An Erratum for this article was reported online in Psychology of Men & Masculinities on Mar 18 2021 (see record 2021-36794-001). In the article “The Interaction of Child–Father Attachment and Child–Mother Attachment in the Prediction of Observed Coparenting” by Jean-François Bureau, Audrey-Ann Deneault, Kim Yurkowski, Jodi Martin, Jeffry Quan, Sage Sezlik, and Camille Guérin-Marion (Psychology of Men & Masculinities, Advance online publication. July 30, 2020. https://doi.org/10.1037/men0000309), the visual representation of interaction effects was erroneously the same in both Figure 2 and Figure 3. Figure 3 depicted the right values of simple slopes, but the wrong visual representation of them. All versions of this article have been corrected.] A number of studies have examined the role of coparenting relationships on the development of children’s attachment to their mothers and fathers. However, previous research tends to interpret this link as unidirectional, thereby ignoring the possibility that, in reverse, child–parent attachment relationships could also predict the quality of the coparenting relationship. Furthermore, there is limited work examining how the child–father and the child–mother attachment relationships may interact to predict coparenting. In response to these limitations, the current study drew from an integrative family systems framework and observational measures to examine these possible relations in biparental heterosexual families. To assess child–parent attachment security, 144 preschool-aged children (83 girls; M = 46.89 months, SD = 8.77) completed independent separation–reunion procedures with their mother and father during counterbalanced laboratory visits. During a subsequent home visit, parents engaged in triadic play with their child, from which coparenting cooperation and competition were evaluated. Results showed that child–mother and child–father attachment security were not independent predictors of coparenting; rather, their interaction significantly predicted the quality of the coparenting relationship. In line with theoretical models calling for a family systems approach, study findings highlight the importance of considering the interactive effects of child–father and child–mother attachment relationships when examining family dynamics. (PsycInfo Database Record (c) 2021 APA, all rights reserved) Public Significance Statement: The current study suggests that the interaction between children’s attachment security toward their father and mother is a more important predictor of the quality of the coparenting relationship than is either individual child–parent attachment relationship. On a broader level, these results show the need to consider the interplay between the child–father and the child–mother relationship when assessing family dynamics. At a more specific level, we also show that there is lower cooperation and higher competition when child–mother security is high but child–father security is low, whereas there is higher cooperation and lower competition when both child–parent attachment relationships present high levels of security. These results suggest that when mothers are successful in fostering a secure attachment relationship, whereas fathers are not, the coparenting relationship may suffer as a result of increased competition and decreased cooperation between parents. As such, assuming positive family dynamics based on the examination of one relationship in isolation might be short-sighted. (PsycInfo Database Record (c) 2021 APA, all rights reserved) © 2020 American Psychological Association