A few weeks into the marking period, the author's eighth-grade students took an all-essay literature test. While grading the tests, she noticed that students made many grammatical errors. It seemed clear that a new approach to grammar instruction was necessary. Staring at this stack of essay tests draws the author in to the concept of metacognition. Metacognition is essentially the act of thinking about one's own thinking. Research has shown that metacognitive thinking has a positive impact on academic success in the areas of standardized tests, reading comprehension, and writing. In this article, the author introduces metacognition in her grammar instruction, and discusses how she uses metacognition to improve students' grammar knowledge.