2015 Revised National Curriculum emphasizes the practice of competency-based curriculum that aims to foster students equipped with core competencies required in future societies. In this study, as a key predictor of teachers’ practice of competency-based curriculum, we focused on teachers’ implicit theories of intelligence (i.e., mindset), or one’s beliefs about changeability of intelligence. Specifically, the purpose of this study was to identify multiple profiles based on teachers’ implicit theories of intelligence, including entity theory (fixed mindset) and incremental theory (growth mindset), and then to examine how these profiles predict teachers’ practice of competency-based curriculum. To this end, 330 in-service teachers in Seoul and Daejeon were asked to respond questionnaire about their implicit theories of intelligence and practice of competency-based curriculum. Five profiles were identified: ‘moderate-high growth mindset (41%)’, ‘high growth mindset (4%)’, ‘moderate mixed mindset (35%)’, ‘moderate-high fixed mindset (17%)’, ‘high mixed mindset (3%)’. Overall, the ‘high mixed mindset’ and ‘high growth mindset’ profiles showed the highest levels of practice of competency-based curriculum, but there were no significant differences between the two profiles. In contrast, the ‘moderate-high fixed mindset’ profile characterized by relatively high fixed mindset alongside the lowest growth mindset showed the lowest levels of practice of competency-based curriculum. These results indicated that teachers’ practice levels of competency-based curriculum are higher as their growth mindset is higher. Therefore, it is important to support teachers’ growth mindset about intelligence to promote students’ core competencies in the 2015 Revised National Curriculum.