Associations of oxytocin receptor gene ( OXTR) variants and autism spectrum disorders (ASD) have been reported in earlier studies; in one of the studies associations with IQ and daily living skills were found additionally. Variations of the oxytocin receptor gene might also regulate affect, attachment and separation beyond the diagnostic borders of autism. We tested hypotheses of associations between positive and negative affects and social and emotional loneliness (285 adults), IQ (117 adolescents) and polymorphisms of the oxytocin receptor gene ( OXTR rs53576, rs2254298 and rs2228485) in normal subjects. Individuals with the oxytocin OXTR rs53576 A/A genotype showed lower positive affect scores ( F = 5.532, df = 1; p = 0.019). This effect was restricted to males ( F = 13.098, df = 1; p = 0.00047). Haplotypes constructed with the three markers were associated with positive affect ( p = 0.0012), negative affect ( p < 0.0001) and emotional loneliness ( p < 0.0001). Non-verbal intelligence was significantly reduced in rs53576 A/A adolescents ( T = 2.247, p = 0.027). Our findings support a role for the oxytocin receptor haplotypes in the generation of affectivity, emotional loneliness and IQ.