The purpose of this study was to reveal final year pre-service science teachers' sources of science teaching self-efficacy beliefs. Research on the sources of pre-service teachers' self-efficacy beliefs is a promising field of research. However, the number of studies examining the sources of pre-service teachers' teaching self-efficacy in a special teaching domain is limited. Two hundred thirty-eight final-year pre-service science teachers constituted the sample of the current quantitative study. Data were gathered through two measures assessing final year preservice science teachers' science teaching self-efficacy beliefs in classroom management, student engagement, and instructional strategies, and sources of these beliefs. Data were analyzed by using descriptive and inferential statistics. Means, standard deviations, and bivariate correlations were performed for descriptive statistics, and regression analyses were performed for inferential statistics. Regression analyses showed that mastery experiences were the primary source of self-efficacy for classroom management ([beta]=0.41), student engagement ([beta]=0.47), and instructional strategies ([beta]=47), followed by verbal persuasions. While emotional states were the only negative predictor of prospective science teachers' self-efficacy beliefs related to classroom management ([beta]=-0.11), student engagement ([beta]=-0.14), and instructional strategies ([beta]=-0.14), vicarious experiences were not found to be a significant predictor of any dimension of self-efficacy beliefs. Teacher preparation programs are advised to pay more attention to teaching practice and micro-teaching courses and provide experienced mentor teacher models to pre-service science teachers. Findings are discussed. [Note: The issue number (7) shown on the PDF is incorrect. The correct citation for this article is v8 n4.]