Asperger syndrome or Aspergers syndrome is an autism spectrum disorder that is characterized by significant difficulties in social interaction, along with restricted and repetitive patterns of behavior and interests. It differs from other autism spectrum disorders by its relative preservation of linguistic (language development) and cognitive development. Although not required for diagnosis, physical clumsiness and atypical use of language are frequently reported.

Asperger syndrome is named for the Austrian pediatrician Hans Asperger who, in 1944, described children in his practice who lacked nonverbal communication skills, demonstrated limited empathy with their peers, and were physically clumsy. Fifty years later, it was standardized as a diagnosis (medical diagnosis), but many questions remain about aspects of the disorder. For example, there is doubt about whether it is distinct from high-functioning autism (HFA); partly because of this, its prevalence is not firmly established. The diagnosis of Aspergers has been proposed to be eliminated, replaced by a diagnosis of autism spectrum disorder on a severity scale.

The exact cause (etiology) is unknown, although research supports the likelihood of a genetic (genetics) basis; brain imaging (neuroimaging) techniques have not identified a clear common pathology. There is no single treatment, and the effectiveness of particular interventions is supported by only limited data. Intervention is aimed at improving symptoms and function. The mainstay of management is behavioral therapy, focusing on specific deficits to address poor communication skills, obsessive or repetitive routines, and physical clumsiness. Most individuals improve over time, but difficulties with communication, social adjustment and independent living continue into adulthood. Some researchers and people with Aspergers have advocated a shift in attitudes toward the view that it is a difference, rather than a disability that must be treated or cured.