Variation in the oxytocin receptor (OXTR) gene may partly explain individual differences in oxytocin-related social behavior. Two single nucleotide polymorphisms (SNPs) have been suggested as promising candidates: rs53576 and rs2254298, although the results of studies were not consistent. We carried out meta-analyses for these two SNPs, covering five domains of outcomes: (a) biology, (b) personality, (c) social behavior, (d) psychopathology, and (e) autism, on the basis of 82 pertinent effect sizes, 48 for OXTR rs53576 (N=17 559) and 34 for OXTR rs2254298 (N=13 547). Combined effect sizes did not differ from zero in any of the domains, nor for all domains combined. Clinical status, age, and sex did not moderate the effect sizes. Minor allele frequency was related to ethnicity, with significantly lower minor allele frequencies in samples with predominantly Caucasian participants. The domain of biological functioning seemed most promising, but comprised few studies. We conclude that so far two of the most intensively studied OXTR SNPs (rs53576 and rs2254298) failed to explain a significant part of human social behavior.