Objectives: One-Session Treatment (OST), a three-hour treatment which includes psychoeducation, exposure, participant modeling, cognitive challenges, and positive reinforcement, has been shown to be effective for the treatment of childhood phobias. Several comorbid anxiety conditions such as Generalized Anxiety Disorder and Social Anxiety Disorder have been shown to have little or no negative effects on treatment outcomes for OST whereas others such as Attention-Deficit Hyperactivity Disorder have been shown to compromise treatment outcomes. This study sought to examine the initial efficacy of OST for children with a behavioral profile demonstrating specific traits of Autism Spectrum Disorder (ASD). We undertook this exploratory study to determine the feasibility and potential efficacy of this brief treatment with these youth. Methods: Two variations of the treatment were trialed. In the OST condition, the child alone received treatment with minimal parental involvement. In the Augmented OST condition, two clinicians were assigned to each family: one clinician worked with the child and the other with the parent. Families in both treatments returned for follow-up assessments one-week, 6-months, and 1-year later. Results: A repeated-measures ANOVA revealed significant reductions in phobia severity as well as increases in overall functioning for both forms of treatment. Conclusions: These results suggest that OST may be an effective intervention for children with ASD traits who evince SPs. Future controlled studies will need to examine the efficacy of this brief intervention with carefully diagnosed youth with ASD as well as explore specific components that make it effective for these children.