Teachers are not just teachers of content. Educators lay the groundwork for how students make sense of the world around them by focusing on tools and strategies that emphasize awareness of knowledge and the application of it. A key factor in engaging in that process is understanding how language and literacy develop in students. The development of language and literacy does not just occur within the four walls of the English language arts classroom but takes place in all content areas. The Next Generation Science Standards highlight the role of language and literacy in the science classroom. This qualitative study examines how science teachers understand the Next Generation Science Standards and the application of metacognitive strategies that target language and literacy within school sites of differing socioeconomic backgrounds. Applying the theoretical framework of metacognition, this study explores teachers' understanding of metacognitive development and whether or not students are tasked with gaining awareness of how they process information. Data collection for this study included teacher interviews, two classroom observations, and post-observation interviews of five public middle school science teachers in two districts. The data collected from teacher interviews and classroom observations suggest that there have been a number of instructional challenges faced by middle school science teachers when implementing the new standards ranging from simply learning the new standards and understanding the integrated science content, to applying a focus on academic language and science literacy in their classroom. The findings suggest that there is a basic understanding of a metacognitive approach to instruction, but teachers struggled to identify whether or not they effectively implemented the approach. Participating teachers were challenged with their own level of confidence in regards to the successful application of metacognitive strategies. Furthermore, findings indicate that regardless of the socioeconomic setting students in middle school are all developing their ability to reason, posing an instructional challenge to educators. However, students with low-SES backgrounds require more instructional supports in order to access academic language, develop literacy, and build background knowledge of the content. Considering the findings of this study, the researcher recommends continuing to support education policy that validates and advances the work of the new standards, making explicit the need for metacognitive practice and strategies within teacher preparation programs, and developing targeted professional development to spur professional collaboration and application of best practices within the science content. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]