“…Although many studies (Arslan, 2012;Britner and Parajes, 2006;Chin and Kameoka, 2002;Gainor and Lent, 1998;Kiran and Sungur, 2012;Klassen, 2004;Lent and Lopez, 1992;Luzzo, et al, 1999;Matsui, et al, 1990;Johnson, Pajares, andUsher, 2006, 2007;Usher, 2009;Wang, 2004) have tried to examine sources contributing to students' self-efficacy, the findings are not consistent. Bandura (1986), Johnson, et al (2007, Kiran and Sungur, (2012), and Luzzo, et al (1999), believed that mastery experience was the most powerful source, while Bentz (2010), Hamman, Olivarez, & Steven (2006), Hampton (1998), Klassen (2004), Luangpipat & Padgate (2015), Matsui et al (1990), and Pajares and Usher (2006) showed that vicarious experience became the highest factor related to the students' self-efficacy. Social persuasion became a vital source of self-efficacy in the work of Chin and Kameoka (2002), Gainor and Lent (1998), and Wang (2004).…”