The Social skills Observation Measure (SOM) is a direct observation method for social skills used in naturalistic everyday situations in school. This study describes the development of the SOM and investigates its psychometric properties in 86 children with Autism spectrum disorder, aged 9.8-13.1 years. The interrater reliability was found to be good to excellent. The convergent validity was low in relation to parent and teacher reports of social skills, and also to parent interview on adaptive social functioning. Therefore this direct observation seems to provide additional information on the frequency and quality of social behaviors in daily life situations. As such it contributes to parent and teacher information as a blind measurement to evaluate Social Skills Training.