Language abilities in adolescents with autism spectrum disorders (ASDs) are variable and can be challenging to ascertain with confidence. This study aimed to compare and evaluate different forms of language assessment: standardized language testing, narrative analysis and parent/teacher reports. 14 adolescents with ASD and 14 typically developing adolescents matched on age, gender and nonverbal ability were assessed using a number of standardized assessments for receptive and expressive language skills, a standardized narrative test, two experimental narrative assessments and a parent/teacher report measure of pragmatics. The findings were that, although adolescents with ASD scored within the normal range on expressive and receptive language, their performance on narrative tasks revealed difficulties with both structural and evaluative language. It should be noted that both teachers and parents rated the pragmatic language skills of the young people with ASD as significantly lower than those of the typically developing group but parents were more likely than teachers to additionally identify difficulties in speech and syntax. The implications of these results for professionals in terms of assessing the language skills of adolescents with ASD and for the planning of appropriate intervention are discussed.