Many students continue to experience reading difficulties into their secondary-school years. Difficulties include poor word decoding, limited vocabulary knowledge, and deficits in working memory capacity. Such difficulties limit the ability of students to acquire new knowledge and be successful in content-area classes. In this article, we describe a curriculum-based measure, vocabulary matching, that teachers can use to assess and monitor the performance of students with reading difficulties in the content areas. Vocabulary matching, has been found to be a valid and reliable measure of performance and progress in content areas. A case study is provided to illustrate the use of vocabulary matching in content-area instruction.