The aim of this study was to comparatively examine in-service physical education teachers' and pre-service physical education teachers' levels of belief in education. This study, which was carried out with the participation of physical education teachers (n=266) employed in various cities of Turkey, as well as first grade (n=73) and fourth grade (n=64) pre-service physical education teachers studying at Balıkesir, Manisa Celal Bayar and Muğla Sıtkı Koçman Universities, was conducted using a survey model. The 'Scale of Teachers' Levels of Belief in Education' developed by Akın and Yıldırım (2015) was used as the data collection tool in the research. For the data analysis, descriptive statistics, independent samples t-test, one-way analysis of variance, and Scheffé's test were utilised. As a result of the research, it was determined that physical education teachers and pre-service teachers partially believed that the general aims of education were achieved, while they believed that the aims of education related to socialisation and all-round development were achieved more than the aims of education regarding individual differences. In the study, it was found that pre-service teachers believed in education more than in-service teachers, and that teachers' professional seniority was an important factor affecting levels of belief in education. In future research, qualitative studies and mixed design studies should be conducted in order to obtain more in-depth information related to revealing the reasons for in-service teachers' and/or pre-service teachers' partial and low levels of belief in education and to suggesting solutions. Furthermore, future studies with a correlational design aimed at determining the relationships of teachers' levels of belief in education with their levels of organisational commitment, professional burnout, motivation and alienation and with their perceptions towards the profession will contribute to better understanding of the phenomenon of belief in education.