Using data from a national family survey, the authors describe the adult lives (i.e., residence, employment, level of assistance needed with everyday life, friendships, and leisure activities) of 328 adults with the full mutation of the FMR1 gene and identify characteristics related to independence in these domains. Level of functional skills was the strongest predictor of independence in adult life for men, whereas ability to interact appropriately was the strongest predictor for women. Co-occurring mental health conditions influenced independence in adult life for men and women, in particular, autism spectrum disorders for men and affect problems for women. Services for adults with fragile X syndrome should not only target functional skills but interpersonal skills and co-occurring mental health conditions.