Requests for pathological demand avoidance diagnoses have increased over recent years but pathological demand avoidance remains a controversial issue. We undertook a systematic review of peer-reviewed studies of pathological demand avoidance, using standardised appraisal and synthesis methods, to assess how pathological demand avoidance is identified and to explore the relationships between pathological demand avoidance, autism and other developmental/psychiatric disorders. A search of PsycINFO/PubMed/MEDLINE/Embase identified 13 studies meeting inclusion criteria. Narrative synthesis was chosen due to methodological heterogeneity of the identified studies. Autistic children/adolescents constituted the majority of participants in most studies. Most studies provided clearly defined inclusion criteria together with adequate descriptions of participants and study settings. Almost all studies relied on the parental report of pathological demand avoidance symptoms/diagnosis. Identification of pathological demand avoidance in all studies seemed to be, directly or indirectly, based on the criteria developed by Newson et al. While eight studies used objective criteria for the identification of pathological demand avoidance, the measures used have methodological limitations. Though associations with anxiety have been reported, few studies took account of possible relationships between pathological demand avoidance and other conditions, such as anxiety. Methodological limitations restrict current conclusions regarding the uniformity or stability of the constellation of behaviours associated with pathological demand avoidance or the characteristics of individuals displaying them. Clinical implications of current research are discussed.