Teacher self-efficacy and individual innovativeness in English language teaching are critical concepts in regard to improving the quality of education and supporting teachers' professional development. Accordingly, this study aims to investigate the relationship between English language teachers’ self-efficacy and individual innovativeness levels and the predictive effect of self-efficacy on individual innovativeness. In addition, it is also examined whether teacher self-efficacy and individual innovativeness variables differ in terms of gender, age, and seniority year, faculty of graduation, educational status, school level worked at, and type of school demographic variables. The research was conducted in accordance with the correlational research model. "Teacher Self-Efficacy Scale" and "Individual Innovativeness Scale" were used as the instruments of gathering the data. The sample of the study consisted of 306 participants, who volunteered to take part in the study and who were working as English teachers in educational institutions in Istanbul. Of the teachers, 199 (65%) were female and 107 (35%) were male. To analyze the data, IBM SPSS Statistics 22 program was used. The findings of the study show that there is a moderate positive relationship between English language teachers' self-efficacy beliefs and individual innovativeness levels. At the same time, English language teachers' self-efficacy beliefs explain 18% of individual innovativeness.