This study investigates the relationship between democratic classroom environment and student engagement and its three dimensions: cognitive engagement, emotional engagement and behavioral engagement. Previous research has extensively reported about the positive relationship between democratic classroom environment and student engagement. However, these studies have evaluated only the relationship between democratic classroom environment and student engagement neglecting the three dimensions. This study contributes to this gap by examining the three dimensions as well. Thus, the paper had two aims: First to investigate the relationship between democratic classroom and the three dimensions of classroom engagement: behavioral engagement, emotional engagement and cognitive engagement and second, to examine the moderating role of teacher between democratic classroom and student engagement. A survey questionnaire was utilized to collect data from secondary school teachers. Since the study was based on correlation method, therefore, regression analysis were conducted to test the hypotheses of the study and to analyze the relationship between the variables. The findings of the study showed that there is a strong positive correlation between democratic classroom environment and student engagement and its three dimensions: behavioral, emotional and cognitive. The study also discovered that teacher moderates the relationship between democratic classroom environment and student engagement. On the basis of the results, the paper concludes that teacher plays an important role in the behavioral, emotional and cognitive engagement of students in the teaching and learning process.