Given the importance of classroom acoustics in the academic performance of school grade students, this research aims to assess the acoustical performance of a number of primary and secondary grade classrooms in public schools in Medellin, Colombia. Standardized measurements of classroom noise and reverberation time were taken in 26 classrooms located in seven public schools. The results revealed excessive noise and reverberation problems in all the classrooms assessed. The cause of this poor acoustical performance seems to be an inappropriate architectural design that prioritizes natural ventilation over classroom sound insulation and the lack of sound absorption materials to control classroom reverberation.