A growing body of research suggests that, compared with single parent-child attachment relationships, child developmental outcomes may be better understood by examining the configurations of child-mother and child-father attachment relationships (i.e., attachment networks). Moreover, some studies have demonstrated an above-chance level chance of concordance between the quality of child-mother and child-father attachment relationships, and child temperament has been offered as a plausible explanation for such concordance. To assess whether temperament plays a role in the development of different attachment network configurations, in this preregistered individual participant data meta-analysis we tested the degree to which the temperament dimension of negative emotionality predicts the number of secure, insecure-avoidant, insecure-resistant, and disorganized attachment relationships a child has with mother and father. Data included in the linear mixed effects analyses were collected from seven studies sampling 872 children (49% female; 83% White). Negative emotionality significantly predicted the number of secure ( = -0.12) and insecure-resistant ( = 0.11), but not insecure-avoidant ( = 0.04) or disorganized ( = 0.08) attachment relationships. Nonpreregistered exploratory analyses indicated higher negative emotionality in children with insecure-resistant attachment relationships with both parents compared to those with one or none ( = 0.19), suggesting that temperament plays a small yet significant role in child-mother/child-father insecure-resistant attachment relationships concordance. Taken together, results from this study prompt a more in-depth examination of the mechanism underlying the small yet significantly higher chance that children with increased negative emotionality have for developing multiple insecure-resistant attachment relationships. (PsycInfo Database Record (c) 2024 APA, all rights reserved).