Purpose <p>Caregivers of children with neurodevelopmental disorders (NDDs) are highly susceptible to affiliate stigma. Although parental trait mindfulness is recognized as a protective factor, the mechanisms through which it protects against stigma remain unclear. This study tested a serial mediation model to investigate whether the association between parental trait mindfulness and affiliate stigma is sequentially mediated by caregivers’ perceptions of child problem behaviors and their own parenting stress.</p> Methods <p>This cross-sectional study recruited 358 parents of children with NDDs. Participants completed the Affiliate Stigma Scale, the Five Facet Mindfulness Questionnaire, the Parenting Stress Index-Short Form, and the Strengths and Difficulties Questionnaire.</p> Results <p>Higher parental trait mindfulness was directly associated with lower affiliate stigma (β = −0.18). The hypothesized serial mediation model was supported by the results. Higher trait mindfulness predicted lower perceived child problem behaviors (β = −0.34), which subsequently predicted lower parenting stress (β = 0.54), ultimately leading to reduced affiliate stigma (β = 0.51). Additionally, trait mindfulness directly predicted lower parenting stress (β = −0.20). The total indirect effect was significant, indicating that perceived problem behaviors and parenting stress are crucial mechanisms elucidating the mindfulness-stigma relationship.</p> Conclusion <p>Parental trait mindfulness protects against affiliate stigma both directly and indirectly by altering parents’ perceptions of their child’s behaviors and reducing their parenting stress. These findings suggest that interventions designed to enhance parental mindfulness could be a potent strategy for mitigating stigma and improving caregiver well-being in families of children with NDDs.</p>