Developing the high levels of reading proficiency necessary to navigate the secondary curriculum is challenging for ELLs, but it is an essential component of academic success in their secondary and subsequent post-secondary education. Despite the importance of understanding the literacy needs of this population, research documenting the reading practices that adolescent ELLs experience in secondary school classrooms is strikingly rare. Particularly absent from this area is research conducted from a sociocultural perspective which foregrounds the examination of the contexts of students' reading experiences. This paucity in research limits our understanding of the nature of the difficulties students encounter in classroom contexts, thus impeding the ability of educators to develop appropriate methods for support that would improve the opportunities that students have to learn. The current study aims at addressing this problem by investigating the in-school reading practices and experiences of high school ELLs through the lens of New Literacy Studies. This study has been designed as a multiple case study, incorporating diverse qualitative research methods including ethnographic observations, semi-structured interviews, collection of artifacts, and the think-aloud method from cultural perspectives. These data sources are analyzed using open coding and axial coding procedures, along with the constant comparative method proposed by Glaser and Strauss. Findings revealed that students' engagement in reading and their reading practices differed according to their individual classroom contexts, such as the types of texts used during instruction, reading-related interactions, and teacher-student relationships. Students demonstrated improved reading practices and skills when they interacted with disciplinary texts, particularly when they had appropriate scaffolding and support to make those texts comprehensible. In terms of social interactions and relationships in the classroom, fostering caring, learning-focused relationships and the setting of higher expectations for students were shown to contribute towards classroom environments that encouraged learning, rather than reactive disciplinary policies which framed students in deficit ways. The results of this study highlight the importance for educators to consider the varied ways in which school contexts influence students' learning and to use those findings to inform how to create contexts that support learning of students with diverse backgrounds and needs. This study builds a knowledge base on the population who has been "overlooked and underserved" both in research and practice, providing insights into the development of appropriate instructional responses to meet the needs of struggling adolescent readers and English language learners. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]