Anxiety disorders are among the most common co-occurring disorders for individuals with ASD. Several adaptations to cognitive behavioral approaches have been proposed for this population (Moree & Davis, 2010). The current study examined feasibility and preliminary efficacy of an ASD-specific adaptation of one-session treatment (OST) for specific phobia (SP). Standard OST consists of one 3-h session followed by four weekly phone calls. Modifications for ASD included increased parental involvement, use of visual aids, and inclusion of four 1-h booster sessions in place of the four weekly phone calls. Visual inspection and Friedman tests revealed significant reductions in fear ratings and phobia severity from pre- to post-treatment and follow-up assessments. Modest changes were observed in behavioral avoidance. These findings provide initial evidence that this treatment merits further study.