This dissertation explores the transformative evolution of online learning, focusing on its role in K-12 online education and the critical issue of student engagement. Tracing its origins from early correspondence courses to today's dynamic, technology-driven platforms, this research examines how online learning has revolutionized educational access, flexibility, and engagement. The study highlights the significant milestones in the evolution of online education, noting the substantial impact of technological advancements that have made learning more interactive, engaging, and personalized (Haleem et al., 2022). Focusing on K-12 education, the dissertation examines how online learning has enabled personalized instruction, self-paced learning, and broader access to diverse educational resources (Borup, 2016). Despite its advantages and growing popularity, concerns about its effectiveness in engaging students and fostering deep and meaningful learning experiences still persist. This study delves into these concerns to understand what teachers perceive as key factors influencing student engagement in online environments. This research aims to unravel educators' challenges in this new digital landscape and proposes effective strategies to enhance student engagement and educational outcomes in K-12 online settings. Ultimately, this study provided valuable insights into the evolving landscape of online learning, offering a deeper analysis of its effectiveness in the K-12 sector and suggesting practical solutions to enhance the quality and impact of online learning. The study contributes significantly to the ongoing discourse on optimizing online learning technologies, particularly in adapting to learners' diverse needs and preferences within online learning environments. [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.]