The aim of this research was to understand the prediction level of primary teachers' selfefficacy of constructivism on their preferred teaching styles in the learning-teaching process. Quantitative research methods were used in the study. In this study, "Teaching Style Scale" developed by Eskici (2013) and the "Self-Efficacy Belief Scale for Teachers' Constructivist Approach" conducted by Üredi (2006) applied to 303 primary school teachers working in Süleymanpaşa, Çorlu and Çerkezköy districts of Tekirdağ. Obtained data were analyzed with SPSS 20 program. Since the obtained data were normally distributed, descriptive statistics were calculated using parametric tests. It was concluded that primary school teachers preferred Facilitator/Personal Model/Expert teaching style most, and their self-efficacy beliefs were high. In order to examine the relationship between teachers' preferred teaching styles and constructivist self-efficacy beliefs, Pearson Correlation coefficient was calculated. To understand the prediction level of primary teachers' self-efficacy beliefs of constructivism on their preferred teaching styles regression analysis was applied to the data. There was a moderate level of relationship between constructivist self-efficacy beliefs and instructional style preferences of primary school teachers, while the predictor was higher in Delegator/Facilitator/Expert teaching style.