This chapter defines neurodevelopmental disorders, and examines the medical, psychosocial, and vocational aspects of two neurodevelopmental disorders that are increasing in the U.S. population: autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). It provides populations at risk of being diagnosed with ASD or ADHD, and distinguishes key considerations for outreach, eligibility determination, and rehabilitation assessment and planning. The chapter considers services to be included in the rehabilitation plan to facilitate goal achievement for consumers with ASD or ADHD, and examines evidence-based practices in job development, placement, and retention. Both ASD and ADHD can be accompanied by co-occurring psychiatric disabilities. Counseling and guidance are always individualized to the unique characteristics, rehabilitation needs, and preferences of each rehabilitation consumer. Rehabilitation counselors must also take into consideration the importance of family involvement in the transition and rehabilitation of youths with ASD and ADHD.