The long-running National Survey of Schools project is part of the New Zealand Council for Educational Research's (NZCER's) Te Pae Tawhiti programme of research, funded through the Ministry of Education. NZCER has run a national survey of English-medium secondary schools every 3 years since 2003. For the 2021 National Survey of Secondary Schools, we surveyed a sample of 5,376 teachers, randomly chosen from a stratified sample of Years 9-13 and Years 7-13 secondary schools to ensure national representation of schools across all deciles. A total of 1,093 teachers responded to the survey over two data collection waves, giving a nationally representative picture in terms of school decile. This report covers all the questions asked of teachers, reported in six sections: (1) NCEA changes and integration of matauranga Maori; (2) Teaching and learning; (3) Student wellbeing; (4) Supporting Maori teachers; (5) Supporting Pacific learners; and (6) Teachers' work, the new Professional Growth Cycle, and PLD.