Specifically in the field of language teaching, it has been recognized that metacognitive strategies maximize language acquisition and improve performance. But despite this, it appears that few teachers currently consider metacognition in their teaching practices. The current study adopted a qualitative design to focus on the reasons that inhibit teachers in French-speaking Belgium from prompting their students to engage in metacognition in first-language (L1) lessons. Semistructured interviews were conducted with seven teachers. The teachers in our sample believed that use of metacognitive strategies can provide benefits for students. But despite this, they explicitly said that they do not prompt their students to engage in metacognition in L1 language lessons. And this for seven specific reasons, as outlined in the article. Knowing these reasons allows us to target the points of attention to be had in training teachers in metacognition in L1.