Assessment has always been one of the most crucial stages of the teaching process at all educational levels. So much so that for many years the evaluation was considered as an activity addressed only to students to determine their achievements. However, to transform the teaching and learning processes, students should not only be assessed for them to identify their weaknesses or strengths. Assessment as a formative purpose should allow students to reflect on the way they learn and encourage them to improve. Metacognition applied to this process of teaching and learning English is essential because it promotes self-regulation and reflection, helps identify strengths and weaknesses, and facilitates feedback between students and teachers.