Eurasian Journal of Educational Research, Issue 43, Spring 2011, 188-205 188 Gender Differences in Geometry and Mathematics Achievement and Self-efficacy Beliefs in Geometry Ahmet Erdoğan ∗ Mustafa Baloğlu ∗∗ Şahin Kesici ∗∗∗ Suggested Citation: Erdoğan, A., Baloğlu, M., & Kesici, Ş. (2011). Gender differences in geometry and mathematics achievement and self-efficacy beliefs in geometry. Egitim Arastirmalari-Eurasian Journal of Educational Research, 43, 188-205. Abstract Problem Statement: Individual differences in education have great importance. Such differences become particularly crucial in disciplines, such as mathematics and geometry. One of the most frequently investigated individual differences is gender-related. Gender differences in mathematics may be different depending upon the particular area of mathematics. Therefore, gender differences in geometry performance and geometry efficacy deserve attention. Purpose of Study: Present study aimed to investigate gender differences in mathematics course achievement, geometry course achievement and geometry self-efficacy. Methods: A total of 199 high school sophomores voluntarily participated in the study. Mathematics and geometry end-of-the-year GPAs were obtained from official student records. Students responded to a set of brief demographic questions asking their gender in addition to the Self-efficacy Scale toward Geometry (SESTG). Data were screened for the assumptions of parametric statistics. In order to test mathematics and geometry end-of- the-year achievement differences simultaneously, between men and ∗ Corresponding author: Assist. Prof. Dr., Selcuk University Ahmet Kelesoglu Faculty of Education, Konya, TURKEY, ahmeterdogan@selcuk.edu.tr ∗∗ Prof. Dr., Gaziosmanpasa University Faculty of Education, Tokat, TURKEY, baloglu@hotmail.com ∗∗∗ Assoc. Prof. Dr., Selcuk University Ahmet Kelesoglu Faculty of Education, Konya, TURKEY, sahinkesici@selcuk.edu.tr