This article aims to investigate metacognition as a factor in sustainable development and supporting the role of lifelong learning. The established conceptual definition of metacognition refers to "thinking about thinking," and recently theorists and researchers agree that metacognition refers to the ability to become aware of our thoughts, cognitions, and behaviors, becoming a fundamental aspect of higher cognition. in man. Metacognition can support cognitive awareness and social interaction as well as sustainable development. There is much debate about the changes that occur at the metacognitive level across the lifespan. Metacognitive knowledge is relatively stable and age-dependent, whereas metacognitive regulation is relatively unstable and independent of age, so that in adulthood, key components of metacognition such as: reflective judgment, critical thinking, decision-making, and problem-solving become sets of key skills for education and the workplace. For this very reason, adults whose metacognitive skills are well developed are better problem solvers, are true decision makers and critical thinkers, are more capable and motivated to learn, and are more likely to regulate their emotions (even in difficult situations), manage complex situations and deal with conflict. On the other hand, becoming more metacognitively competent, both academically and professionally and personally, can help maximize this neural plasticity-the brain's ability to change and grow and become, in terms of functionally, smarter. Although, metacognitive skills, once well learned, can become habits of mind that are applied in a wide variety of contexts, it is important to consciously apply appropriate metacognitive skills for sustainable development in all aspects of daily life.