A recent project has investigated acoustical conditions in secondary (high) schools, and examined the effects of a poor acoustic environment on teaching and learning of 11- to 16-year-olds. Around 2600 pupils from suburban secondary schools in England responded to an online questionnaire concerning the acoustic environment in their schools. The questionnaire data highlighted the differential effects of noise reported by more vulnerable learners. A repeated measures experimental study involving 572 pupils examined reading performance under two different classroom noise simulations. Results revealed a complex pattern reflecting noise levels, time of testing and measure of reading performance used. Reading text while exposed to classroom noise of 70 dB resulted in quicker reading but less accuracy in measures of reading comprehension compared with performance in 50 dB. The data further suggested that the pupils were not processing the text as deeply as was evident from their reduced lexical learning. There were also interactions with time of testing highlighting the importance of examining the effects of chronic exposure in addition to single session experimental testing. The test results show that capturing the effects of noise on pupils’ learning in realistic classroom environments raises a number of methodological and analytical problems.