Children with Asperger's syndrome are often reported by their parents as having difficulties communicating affection. This study aimed to develop a valid measure of affectionate behaviour that could be used to investigate and quantify these anecdotal reports and then be used in further intervention research. Using parent and expert focus groups, three measures (Affection for Others Questionnaire, Affection for You Questionnaire and General Affection Questionnaire) were developed with reference to the existing affection literature. The measures were completed by 131 parents of children with a clinician-confirmed diagnosis of Asperger's syndrome. Psychometric assessment of the measures revealed clear factor structures with high internal consistencies and significant concurrent validities. The findings suggest many children with Asperger's syndrome have difficulties with affectionate behaviour that significantly impact their daily functioning and relationships with others, signalling future research needs to develop interventions in this area. Limitations of the research are also discussed.