Objective: Few guidelines are available regarding optimal training models for practitioners delivering cognitive–behavioral therapy (CBT) for anxiety in youth with autism spectrum disorder (ASD). The present study systematically compared 3 instructional conditions for delivering the Facing Your Fears program (FYF) to children with ASD and anxiety. Method: Thirty-four clinicians (Mage = 34 years; 94% women, 88% Caucasian) and an intent-to-treat sample of 91 children with ASD and anxiety (Mage = 11; 84% male 53% Caucasian) met eligibility criteria across 4 sites. A 3-group parallel design via a Latin square procedure was used to randomize 9 teams of clinicians to 1 of 3 training conditions: Manual, Workshop, Workshop-Plus. The effectiveness of instructional condition was assessed via implementation (CBT knowledge, treatment fidelity) and treatment outcomes (reductions in anxiety as measured by the Anxiety Disorders Interview Schedule-Parent (ADIS-P). Results: Clinicians in both Workshop conditions significantly increased CBT knowledge postworkshop, F(1, 18) = 19.8, p