This study examined how content area teachers' literacy knowledge developed during a yearlong professional development initiative focused on using the framework of Question-Answer Relationships (QAR) within explicit instruction. The initiative focused on the metacognitive thinking in which teachers engage during QAR instruction. The participating teachers' knowledge development was measured through their metacognitive understandings as demonstrated by lesson plans and reflective comments. Findings indicate that teachers' metacognitive understanding of the QAR strategy was demonstrated through their declarative and procedural understandings. Teachers successfully enacted a literacy strategy in their content classrooms, understanding that students would become more actively engaged and metacognitive about the content being learned. (Contains 1 table and 2 figures.)