A poor acoustic environment in a school is known to negatively affect pupils' learning and achievement. This paper presents the design and findings of an online questionnaire survey of 11-16 year olds' impressions of their school's acoustic environment. A total of 2588 English secondary school pupils responded to the questionnaire. Factor analysis was used to identify variables which best characterized pupils' impressions of their school's acoustic environment. Four factors, corresponding to ease of hearing in school spaces, sensitivity to noise, the consequences of noise in the classroom, and annoyance to intermittent noise, accounted for 43% of the total variance in pupils' responses to the questionnaire. Analysis of the responses on these factors showed that pupils who reported additional learning needs such as hearing impairment, speaking English as an additional language or receiving learning support reported being significantly more affected by poor school acoustics than pupils reporting no additional learning needs. Older pupils were significantly more sensitive to noise annoyance and to the consequences of poor acoustical conditions on their learning and behaviour than younger pupils. Pupils attending suburban schools featuring cellular classrooms that were not exposed to a nearby noise sources were more positive about their school acoustics than pupils at schools with open plan classroom designs or attending schools that were exposed to external noise sources. The study demonstrates that adolescents are reliable judges of their school's acoustic environment, and have insight into the disruption to teaching and learning caused by poor listening conditions. Furthermore, pupils with additional learning needs are more at risk from the negative effects of poor school acoustics.