Metacognitive skills are widely recognized as critical components of effective learning and lifelong personal development. These skills enable individuals to plan, monitor, regulate, and evaluate their own learning processes, thereby fostering self-directed learning, critical thinking, and adaptability in rapidly changing environments. In the twenty-first century, where continuous learning has become essential for professional success and personal growth, metacognition plays a crucial role in supporting lifelong learning competencies. This study investigates the relationship between metacognitive skills and lifelong learning among higher education students and adult learners. A mixed-method research design involving 700 participants from universities and professional learning environments was employed. Quantitative data were analyzed using descriptive statistics and regression analysis, while qualitative insights were obtained through interviews and reflective learning journals. Findings reveal that strong metacognitive skills significantly contribute to learner autonomy, academic achievement, problem-solving ability, and motivation for continuous learning. The study concludes that integrating metacognitive strategies into educational practices can effectively promote lifelong learning and sustainable personal development.