Pervasive developmental disorders (PDD) are a group of disorders characterized by delays in the development of socialization and communication skills. These disorders are present at birth, but the signs of the disorders usually are noticed during a child's first 3 years of life.

Pervasive developmental disorders include autism, Rett's disorder (or syndrome), Asperger's syndrome (or disorder), childhood disintegrative disorder (CDD), and pervasive developmental disorders not otherwise specified (PDD-NOS). Pervasive developmental disorders may also be called autism spectrum disorder.

The severity of pervasive developmental disorders varies by individual. Treatment for these disorders includes behavioral training, speech and occupational therapy, and parent education and support.