Autism spectrum disorder (ASD) is a neurodevelopmental disorder commonly associated with behavioral challenges. There are few evidence based pharmacological interventions available for the treatment of behavioral symptoms associated with ASD. Cannabidiol (CBD), the non-psychoactive component of cannabis, has potential neuroprotective, antiepileptic, anxiolytic, and antipsychotic effects and may be useful in treating the behavioral symptoms of ASD. We describe the research methods of a 27-week double-blind placebo-controlled cross-over trial of cannabidiol for the treatment of irritability and aggression associated with ASD, utilizing the irritability subscale of the Aberrant Behavior Checklist-2nd edition (ABC-2) as the primary outcome measure. Adverse effects and safety monitoring protocols are included. Several secondary and exploratory outcomes measures also include anxiety, communication, repetitive behaviors, attention, hyperactivity, autism family experience, and telehealth functional behavior assessment. There is a significant need for clinical research exploring alternative medications for the treatment of behavioral symptoms of ASD. Cannabidiol (CBD) is being studied for the management of irritability, aggression, and other problem behaviors associated with ASD.