Although Autism Spectrum Disorders (ASDs) have traditionally been considered a lifelong condition, there appear to be a subset of people who make such significant improvements that they no longer meet diagnostic criteria for autism. The current study examines whether these "optimal outcome" (OO) children and adolescents, despite losing their ASD diagnosis, exhibit Broader Autism Phenotype (BAP) traits and other personality traits that are more often found in those with ASD. Nine zero acquaintance raters evaluated the personality traits of children who have achieved "optimal outcomes" (n=22), high-functioning children with ASD (HFA; n=27), and their typically developing (TD) peers (n=23). HFA children were rated as significantly higher than OO and TD children on overall ratings of BAP traits (Aloofness, Pragmatic Language difficulties, and Rigidity), whereas OO children did not differ from TD children. Compared to HFA children, OO participants displayed a personality profile of higher Extraversion, Agreeableness, Conscientiousness, Openness, and lower Neuroticism. OO and TD children were indistinguishable in overall Big Five personality traits, with the exception of the Extraversion domain, where OO children were rated as "more" extraverted than TD children, and in the domain of Emotional Stability, where OO children were rated as potentially less emotionally stable than TD children. Greater observed extraversion in OO children is consistent with observations of more ADHD-like traits such as being more talkative and less inhibited. Regarding Big Five personality traits, Neuroticism best differentiated the HFA group from the OO and TD groups, whereas Extraversion best differentiated the OO group from the TD group. Likewise, the BAP trait of Rigidity best differentiated the HFA group from the OO and TD groups, whereas the BAP traits of Aloofness, Pragmatic Language Deficits, and Rigidity could not reliably differentiate the OO group from the TD group. Overall, OO children are doing very well. However, residual ADHD-likes symptoms could impact the quality of their relationships, and less emotional stability is associated with greater risk for psychopathology. It is recommended that these symptoms be explicitly evaluated in OO children and targeted for intervention. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]