Teachers frequently happen to be the most influential role models and social change agents in the eyes and minds of young people as well as the whole society in many cultures. Since they are closely involved in promoting the ideas for the goodness of communities and the whole world either as individuals or educators, teachers' behaviours across all aspects of their life are correspondingly valuable. Therefore, what teachers do in and out of school for the benefit of nature, society or humanity is a crucial phenomenon worth studying. With this study, we aimed to identify the motives for and the predictors of PEBs (pro-environmental behaviours) that teachers follow in their personal, professional, or social spheres and specify whether those behaviours are the characteristics of a particular teacher group or not. Designed as a survey, the research was mainly a correlational study exploring the existing relationships between teachers' tendency to adopt PEBs and certain socio-demographics along with internal factors. In this inquiry, we surveyed 330 Turkish in-service teachers representing different educational settings across the country through a cross-sectional online questionnaire and performed descriptive statistics and multiple regression analyses with the help of the software STATA. Based on the findings of the study, we presented suggestions for policy and practice in teacher education as well as implications for future research on pro-environmental practices and environmental education.