In spite of increasing interest in cognitive behaviour therapy for emotional disorders in children with autism spectrum disorders (ASD), little research has explored the relevance of the cognitive model in this population. This study explores dysfunctional attitudes and perfectionism in boys with ASD and the relationship with anxious and depressive symptoms. Compared to a typically developing group (n = 42), boys with ASD (n = 41) endorsed more dysfunctional attitudes and reported higher emotional symptoms. The relationship between emotional and cognitive variables was weak in both groups, although in the ASD group dysfunctional attitudes were significantly associated with reported obsessive–compulsive symptoms. Reasons for elevated dysfunctional attitudes in the ASD group are discussed and the roles of cognitive inflexibility and social impairments are explored.