Atypical sensory processing is common in autism spectrum disorders (ASD). Specific profiles have been proposed in different age groups, but no study has focused specifically on adolescents. Identifying traits of ASD that are shared by individuals with ASD and their non-affected family members can shed light on the genetic underpinnings of ASD. Eighty adolescents with ASD (64 boys, 16 girls), 56 non-affected adolescent siblings (21 boys, 35 girls) and 33 adolescent controls (18 boys, 15 girls) filled out the Adolescent/Adult Sensory Profile, a self-report questionnaire resulting in four sensory quadrants according to Dunn's model of sensory processing. Adolescents with ASD differed significantly from controls on the quadrants Sensation Seeking and Sensation Avoidance. On quadrant 2 (Sensation Seeking) siblings scored significantly lower than controls and significantly higher than ASD. These results confirm the presence of atypical sensory processing in adolescents with ASD. We argue that reduced Sensation Seeking might be a candidate for an intermediate phenotype. (Contains 1 table.)