Purpose <p>This study aimed to investigate the predictors of parental burnout among Chinese parents of children with developmental disabilities (DD), focusing on the potential nonlinear and interactive effects of socio-demographic characteristics, Big Five personality traits, and parenting perfectionism.</p> Methods <p>A total of 528 parents of children with DD were recruited from various regions in China. Participants completed standardized questionnaires assessing parental burnout, Big Five personality traits, parenting perfectionism, and socio-demographic characteristics. To examine both linear and nonlinear associations between these predictors and parental burnout, we employed generalized linear model (GLM)—the extension of linear regression that accommodates non-normal outcome distributions—and generalized additive model (GAM), which allow for the flexible modeling of nonlinear effects. Interaction effects between personality traits and parenting perfectionism were also tested using GAM.</p> Results <p>Results indicated that GAM outperformed GLM in capturing complex relationships, revealing significant nonlinear associations between parental burnout and several predictors, including parental age, education, income, extraversion, agreeableness, neuroticism, and both dimensions of parenting perfectionism. Notably, personality traits and parenting perfectionism interacted in predicting burnout. For example, high neuroticism combined with high perfectionistic concerns significantly increased the risk of burnout.</p> Conclusion <p>The study underscores the need to consider nonlinear and interactive effects in understanding parental burnout. GAM offers a useful approach for revealing complex patterns, especially in non-Western contexts.</p>