Summary Objectives The aim of the study was to investigate the connections between voice ergonomic risk factors found in classrooms and voice-related problems in teachers. Methods Voice ergonomic assessment was performed in 39 classrooms in 14 elementary schools by means of a Voice Ergonomic Assessment in Work Environment—Handbook and Checklist. The voice ergonomic risk factors assessed included working culture, noise, indoor air quality, working posture, stress, and access to a sound amplifier. Teachers from the above-mentioned classrooms reported their voice symptoms, respiratory tract diseases, and completed a Voice Handicap Index (VHI). Results The more voice ergonomic risk factors found in the classroom the higher were the teachers' total scores on voice symptoms and VHI. Stress was the factor that correlated most strongly with voice symptoms. Poor indoor air quality increased the occurrence of laryngitis. Conclusions Voice ergonomics were poor in the classrooms studied and voice ergonomic risk factors affected the voice. It is important to convey information on voice ergonomics to education administrators and those responsible for school planning and taking care of school buildings.