Sex differences in chronic pain are reported to emerge during adolescence, although it is unclear if this includes responses to treatment. We conducted a meta-analysis to examine whether sex differences were present on outcome variables at pretreatment and whether the efficacy of psychological therapies for pediatric chronic pain differs between boys and girls at posttreatment and follow-up time points. Searches were conducted, extending 2 existing Cochrane reviews of randomized controlled trials examining the efficacy of psychological therapies for chronic and recurrent pain in children and adolescents. Forty-six articles were eligible for inclusion, and data were extracted regarding pain, disability, anxiety, and depression in boys and girls at pretreatment, posttreatment, and follow-up time points. No published study reported outcome data separately by sex, so authors of all studies were contacted and 17 studies provided data. Twice as many girls (n=1760) were enrolled into clinical trials of psychological therapies for pediatric chronic pain than boys (n= 828). Girls reported higher depression and anxiety at pretreatment than boys. Girls with headache also reported significantly greater pretreatment pain severity. Treatment gains were consistent across the sexes. One exception was for posttreatment disability in children with nonheadache pain conditions; girls exhibited a significant effect of treatment relative to control condition (standardized mean difference- -0.50 [-0.80,-0.20], P < 0.01), but no such effect was observed for boys (standardized mean difference = -0.08 [-0.44, 0.28], P =0.66). Future research should examine whether mechanisms of treatment efficacy differ between boys and girls and consider the impact of pretreatment sex differences on response to treatment.