Atypical responses to sensory stimuli are a new criterion in DSM-5 for the diagnosis of an autism spectrum disorder (ASD) but are also reported in other developmental disorders. Using the Short Sensory profile (SSP) and Autism Diagnostic Interview-Revised we compared atypical sensory behaviour (hyper- or hypo-reactivity to sensory input or unusual sensory interests) in children aged 10-14 years with (N = 116) or without an ASD but with special educational needs (SEN; N = 72). Atypical sensory behaviour was reported in 92 % of ASD and 67 % of SEN children. Greater sensory dysfunction was associated with increased autism severity (specifically restricted and repetitive behaviours) and behaviour problems (specifically emotional subscore) on teacher and parent Strengths and Difficulties Questionnaires but not with IQ.