This study aims to investigate the effects of the sources of self-efficacy in mathematics on gifted students' mathematics anxiety. The participants of this study are 260 seventh grade gifted students, who attend science and art centers located in Adana, Bursa, Corum, Elazig, Izmir, Izmit, Kayseri, Konya, Manisa and Salihli. Of all the participants, 51.50 % were female (n=134) and 48.50 % were male (n=126). The Sources of Self-Efficacy in Mathematics Scale was used to determine students' sources of self-efficacy in mathematics and the Mathematics Anxiety Scale was used to determine their levels of mathematics anxiety. The data were analyzed through multiple linear regressions. The results showed that of all the sources of self-efficacy in mathematics, namely personal experiences, vicarious experiences, social persuasions and physiological states, only personal experiences had a significant effect on gifted students' levels of mathematics anxiety. The sources of self-efficacy in mathematics were found to account for about 48% of variance in gifted students' levels of mathematics anxiety. The findings were discussed in the light of theoretical framework.