Metacognition is an essential, but habitually ignored element of 21st century education, which aims to teach students how to learn. 'Meta' is a Greek word meaning 'after', 'behind' or 'beyond'; 'meta' is added to terms such as meta memory, meta comprehension, and metacognition. The lack of consciousness is cognitive self-regulation activities occurring without awareness. According to Flavell, metacognition is broadened knowledge and cognition about cognitive, affective, perceptual, or motor human characteristics. Metacognition knowledge includes knowledge about oneself as a learner and the factors that might affect performance, knowledge about strategies, and knowledge about when and why to use these strategies. Metacognition guideline is the monitoring of one's cognition, which includes planning activities, awareness of comprehension and task performance, and evaluation of the efficacy of monitoring processes and strategies. Aim of the study is to explore the theoretical base of metacognition and to identify the possibility of further research in that area. The main purpose of the study is to identify the lacuna of theoretical use of metacognition. The present study have been under taken keeping the following research questions in mind: What kinds of research have been undertaken so far to validate the theory of metacognition? How can a teacher promote the metacognition ability of a learner? How can metacognition skills enhance pupils' learning? The present theoretical views are extremely useful for teacher educators, developmental psychologists, and teachers.