Developmental Disabilities Institute

UPDATED: December 7, 2021

Developmental Disabilities Institute (DDI) was founded in 1961 to address the special education needs of children with autism and other developmental disabilities and provide therapeutic intervention.

Today, DDI is a dynamic, non-profit, multi-site agency, each day serving hundreds of children and adults with autism and other developmental disabilities, providing educational, residential, habilitative, vocational, transportation, and service coordination support to the Long Island community.

DDI's educational, residential, day, and vocational supports are as diverse as the people we serve. Through more than 60 years of sustained effort, DDI has grown substantially.

Our agency recognizes the unique needs of each person for whom we care and maintains the highest standards of teaching for our children, adults, and families, as well as training for our staff. We pride ourselves on utilizing research-based methods across all agency programs.


  • Languages:
  • English
  • Insurances Accepted:
  • Call for Fee
  • Medicaid
  • Private Insurance


99 Hollywood Dr.
Smithtown, NY 11787
United States



(631) 297-3263


Our Autism Response Team (ART) is specially trained to connect people with autism, their families, and caretakers to information, tools, and resources.

Get in Touch with ART

Autism Speaks does not provide medical or legal advice or services. Rather, Autism Speaks provides general information about autism as a service to the community. The information provided on our website is not a recommendation, referral or endorsement of any resource, therapeutic method, or service provider and does not replace the advice of medical, legal or educational professionals. Autism Speaks has not validated and is not responsible for any information, events, or services provided by third parties. The views and opinions expressed in blogs on our website do not necessarily reflect the views of Autism Speaks.