Autism spectrum disorders (ASD) are associated with cognitive dysfunctions, including mental time travel (MTT). However, findings on diminished MTT ability may be confounded by a number of factors, including the individuals' language ability, factors related to the MTT task and the demographic factors of participants. The present study provided a meta-analysis of MTT ability in people with ASD. The results showed significant overall reductions in MTT ability in people with ASD. Moderator analyses revealed that the variables examined did not explain the reduction in MTT ability. These findings suggest that MTT ability is diminished in people with ASD and that the degree of this diminishment may not depend on the characteristics of measures or demographic variables of people with ASD.