<p>Parents of children with special needs often face persistent mental health challenges. Acceptance and Commitment Therapy (ACT) has shown promise via the psychological flexibility framework, but reported effects have been heterogeneous. We systematically searched PubMed, Web of Science, and the Cochrane Library for randomized controlled trials of ACT delivered to parents of children with special needs that reported standardized effect sizes for parental anxiety. Eleven studies (<i>n</i> = 768) met the inclusion criteria. A fixed-effects meta-analysis revealed that ACT significantly alleviated parental anxiety symptoms (standardized mean difference (SMD) = − 0.26; 95% CI − 0.40 to − 0.12; <i>P</i> = 0.0003). Subgroup analyses indicated that the most substantial effects were observed among parents of children with neurodevelopmental disorders (SMD = − 0.50). Interventions conducted four times a week, lasting 120&#xa0;min per session over 6–8 weeks, resulted in more pronounced effects (SMD = − 0.42). Integrated intervention approaches also produced positive results (SMD = − 0.35). Meta-regression analysis highlighted mean parent age and child condition as key moderators; studies involving parents of children with neurodevelopmental disorders exhibited greater effects (β = −0.37, <i>p</i> = 0.021), while each additional year of parent age correlated with a 0.05-unit increase in SMD (indicating a slightly reduced treatment effect). In summary, ACT seems effective in reducing parental anxiety symptoms among parents of children with special needs, with the most significant advantages noted in high-frequency/high-intensity standardized programs and among those caring for children with neurodevelopmental disorders.</p>