Anxiety in autism is commonly reported by parents, but teacher reports of anxiety in their students with autism have received little attention. This paper presents the results from the first systematic review on anxiety in children with autism at school. Six intervention studies (five of which were based upon cognitive-behavioural therapy) and 26 descriptive/non-experimental studies met inclusion criteria. Sample populations from included studies were frequently drawn from psychiatric clinics, with females and children attending special schools underrepresented, making generalisability of results difficult. Few studies used anxiety-specific measures, with most reporting anxiety-related subscale means from broader emotional/behavioural questionnaires. While 19 studies included multiple informants, which is recommended practice, only seven studies combined parent, teacher and child reports of anxiety. Comparison between informants proved difficult, with varying sample sizes and few studies using the same measure across participant groups. To further our understanding of the presentation of anxiety in children with autism attending school, studies need to include multiple informants and, where possible, extend beyond reporting average scores from broad anxiety subscales to provide descriptions of presentation and symptomatology.