The catechol-O-methyltransferase (COMT) ValMet polymorphism is associated with cognitive functioning in schizophrenia and may predict cognitive training outcomes. This study aimed to explore the contribution of COMT genotype in predicting improvement following Compensatory Cognitive Training (CCT). We conducted mixed factorial analysis of variance to examine COMT genotype as a predictor of response to CCT (i.e. improved cognitive performance) in 41 participants with schizophrenia-spectrum disorders. We also explored the effect of CCT treatment and COMT genotype on psychiatric symptom severity, functional capacity, and subjective quality of life. Met carrier status did not predict CCT treatment outcomes. COMT genotype may exert only modest effects on cognitive training response. Further research with larger samples is needed to establish genetic predictors of response to cognitive training.