Symptoms of autism spectrum disorder may influence alliance in psychotherapy. This study examined therapeutic alliance and its relationship with child characteristics and anxiety treatment outcomes in youth with autism spectrum disorder. Youth (N = 64) with autism spectrum disorder and co-occurring anxiety (7-16 years, IQ > 70) received 16 sessions of modular cognitive-behavioral therapy. Post-treatment therapist, youth and parent ratings of alliance as well as pre- and post-treatment ratings of child behavior were gathered. Ratings of alliance were commensurate to ratings seen in children without autism spectrum disorder. Measures of treatment outcome, but not pretreatment characteristics, were significantly associated with therapist ratings of alliance strength. Data suggest that therapeutic alliance may not be impaired in anxious youth with autism spectrum disorder and may be associated with treatment outcome.