Asperger Syndrome (AS) also known as Autism spectrum disorder which is characterized by difficulties in social interaction, alongside restricted and repetitive patterns of behaviors and interests. Although not required for diagnosis, physical clumsiness and atypical use of language are frequently reported.

The syndrome is named after the Austrian pediatrician Hans Asperger who, in 1944, studied and described children in his practice who lacked nonverbal communication skills, demonstrated limited empathy with their peers, and were physically clumsy. The conception of Asperger syndrome came into existence in 1981 and went through a period of popularization, becoming standardized as a diagnosis in the early 1990s. 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.

It has been proposed that the diagnosis of Asperger's be eliminated, to be replaced by a diagnosis of autism spectrum disorder on a severity scale.

Asperger Syndrome is also known as pervasive developmental disorders (PDD) instead of Autism spectrum disorder. Children with Aspergers Syndrome often find social situations extremely trying and stressful. They frequently have stereotypical patterns of behavior and can be obsessive about very specific interests, in addition to some speech and language peculiarities and issues with non-verbal communication
The extent of the overlap between AS and high-functioning autism is unclear. The current ASD classification is to some extent an artifact of how autism was discovered, and may not reflect the true nature of the spectrum; methodological problems have beset Asperger syndrome as a valid diagnosis from the outset.

One of the proposed changes to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, to be published in May 2013, would eliminate Asperger syndrome as a separate diagnosis, and fold it under autistic disorder (autism spectrum disorder), which would be rated on a severity scale.

Like the diagnosis of Asperger syndrome, the proposed change is controversial, and it has been argued that the syndrome's diagnostic criteria should be broadened. Asperger syndrome is also called Asperger's syndrome (AS), Asperger disorder (AD). There is little consensus among clinical researchers about whether the condition's name should end in "syndrome" or "disorder".

People with AS may not be as withdrawn around others as those with other, more debilitating, forms of autism; they approach others, even if awkwardly. For example, a person with AS may engage in a one-sided, long-winded speech about a favorite topic, while misunderstanding or not recognizing the listener's feelings or reactions, such as a need for privacy or haste to leave. This social awkwardness has been called "active but odd".

This failure to react appropriately to social interaction may appear as disregard for other people's feelings, and may come across as insensitive. However, not all individuals with AS will approach others. Some of them may even display selective mutism, speaking not at all to most people and excessively to specific people. Some may choose to talk only to people they like.