Numerous meta-analyses and reviews have been conducted on the effectiveness of psychological treatment of sexual offenders in reducing recidivism, but no meta-analysis has been done on sexual offenders against children (SOAC) specifically. A moderate treatment effect has been shown in several evaluations of general sexual offenders, while many scholars maintain that the question remains unanswered until an adequate number of effectiveness studies with a strong research design have been carried out. In this meta-analysis, we evaluated 14 studies selected and coded according to Collaborative Outcome Data Committee (CODC) criteria. They included 1,421 adult offenders in psychotherapy and 1,509 nontreated controls, with a minimum average follow-up period of 3 years, published in peer-reviewed journals in 1980 or later. Recidivism was defined as rearrest or reconviction. Study quality was classified into strong, good, weak or rejected. The analysis revealed a treatment effect size of r = .03 for nine studies evaluated as Good or Weak, while all studies yielded an effect size of r = .08, including five studies classified as Rejected. The results show that the available research cannot establish any effect of treatment on SOAC. Despite a large amount of research, only a tiny fraction of studies meet a minimum of scientific standards, and even fewer provide sensible and useful data from which it is possible to draw conclusions.