待分类的广泛性发展障碍(Pervasive Developmental Disorder Not Otherwise Specified；简称PDD-NOS)，亦作非典型自闭症，泛指一般有自闭症倾向，但不能透过其特征而归类为更具体的分类，是自闭症光谱的成员之一、广泛性发展障碍的一种。

PDD-NOS占了自闭症光谱的90%：单单以美国为例，每104个美国男孩里就有一个PDD-NOS儿童，是女童的四倍。

PDD-NOS的征状与自闭症相似，但一般的征状都比较轻微，而且并非所有必要的特征都存在。PDD-NOS与其他非自闭症的分野界线，到现在其实还是很模糊。

A pervasive developmental disorder not otherwise specified (PDD-NOS) is one of the three autism spectrum disorders (ASD) and also one of the five disorders classified as a pervasive developmental disorder (PDD). According to the DSM-IV, PDD-NOS is a diagnosis that is used for "severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific PDD" or for several other disorders. PDD-NOS is often called atypical autism, because the criteria for autistic disorder are not met, for instance because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these. Even though PDD-NOS is considered milder than typical autism, this is not always true. While some characteristics may be milder, others may be more severe.