The impact of metacognitive awareness on students' performance has been examined in the present study. 900 students of grade X participated in the study. Metacognitive awareness was measured using inventory, while performance of students was measured with the help of researcher made test in the subject of chemistry. Results indicated that metacognitive awareness was significantly correlated with the performance of students. The highly metacognitively aware science students performed well on the test. Results further indicated that there was no significant difference in the metacognitive awareness of male and female students.