The current study examined the relationship between early language ability and autistic-like traits in adulthood, utilising data from 644 participants from a longitudinal study of the general population. Language performance at 2 years was measured with the Language Development Survey (LDS), and at 20 years the participants completed the Autism-Spectrum Quotient (AQ). Vocabulary size at 2 years was negatively associated with Total AQ score, as well as scores on the Communication, and Social Skills subscales. Adults who had been late talkers were also more likely to have ‘high’ scores on the Communication subscale. This is the first study to show an association between early language ability and autistic-like traits in adulthood.