Literacy coaching has become a popular professional development approach in the United States over the last decade. To date, there has been little research on the different lived experiences and challenges of literacy coaches working in different contexts. Furthermore, research findings regarding the effectiveness of literacy coaching are inconclusive. To fill the gaps in the literature, this study was designed to explore the nature of literacy coaching in the United States and examine the relationship between literacy coaching and student literacy achievement, both from the perspective of literacy coaches and that of classroom teachers. An embedded mixed methods research design, comprising a main strand and a supplemental strand, was adopted to explore the research questions. In the main strand, 3 literacy coaches were interviewed and observed; in the supplemental strand, 108 classroom teachers completed an online survey featuring both closed-ended and open-ended questions. The findings of this study show that both literacy coaches and classroom teachers perceive that literacy coaching is an effective type of professional development in improving teaching and learning. It is perceived as better than most of the previously used professional development methods (e.g., one-shot workshops, conferences, face-to-face college coursework, online college coursework, and reading professional literature) because literacy coaches can provide timely, on-site, continuous, and personalized assistance to support teacher learning in a self-directed, reflective and collaborative way. The effectiveness of literacy coaching, however, depends in part on the skills and qualifications of literacy coaches, as well as the receptiveness of classroom teachers and the support of administrators. The findings also reveal that literacy coaching is a stressful and demanding job because in order to be effective, literacy coaches have to assume multiple, yet at times, undefined roles. The findings reveal the need for support of literacy coaches in order to help them survive and thrive. The implications of this study include providing a clear job description for coaches, maintaining appropriate coach-teacher ratio, educating administrators about literacy coaching, providing coaches with ongoing professional development opportunities, providing coaches with release time for networking, and providing teachers with the necessary support and release time for working with literacy coaches. [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.]