<![CDATA[This study aims to describe the metacognitive abilities of students with high self-efficacy in solving plane geometry problems. The research employed a qualitative approach using a descriptive research design. The research subject was one seventh-grade junior high school student identified as having high self-efficacy based on the results of a self-efficacy questionnaire. Data were collected through a self-efficacy questionnaire, a plane geometry problem-solving test, and semi-structured interviews. Data were analyzed using the stages of data reduction, data display, and conclusion drawing. Data validity was ensured through technique triangulation by comparing the results of the written test and interviews. The findings revealed that students with high self-efficacy demonstrated strong metacognitive abilities across the three indicators: planning, monitoring, and evaluating. In the planning stage, the student was able to understand the problem, identify known and required information, and develop a systematic problem-solving strategy. During the monitoring stage, the student effectively controlled the problem-solving process by reviewing each calculation, identifying and correcting errors, and modifying strategies when necessary. In the evaluating stage, the student rechecked the final answers, drew appropriate conclusions, and assessed the effectiveness of the strategies used. These findings indicate that high self-efficacy contributes positively to students' ability to regulate their thinking processes while solving mathematical problems. Students with strong self-confidence tend to be more systematic in planning, more careful in monitoring their work, and more reflective in evaluating the outcomes. Therefore, self-efficacy is an important factor in supporting the development of students' metacognitive abilities in solving plane geometry problems effectively, systematically, and accurately.]]>
