In 2020 and 2021, the COVID-19 pandemic prompted schools around the world to quickly shift their instruction from in-person learning to online or hybrid learning to limit the spread of the virus. These changes drastically altered the educational experiences of students, and many teachers lacked adequate time and training to prepare for this challenge. The purpose of this study was to discover how secondary literacy students experienced students' reading engagement during online and hybrid instruction during the COVID-19 pandemic and how secondary literacy teachers made instructional decisions to support students' reading engagement. This qualitative exploratory case study was conducted in a private, co-ed, college-preparatory high school in the Midwestern United States. The study included semi-structured interviews with seven high school English language arts teachers and five semi-structured focus group interviews with a total of 47 students in grades 10 through 12. Students' reading engagement was perceived by both students and teachers to be lower during online and hybrid learning. Both students and teachers perceived online and hybrid learning to be challenging due to a more relaxed context for learning, difficulties with interaction, and changes to curriculum and instruction. Teachers' instructional decisions in online and hybrid learning could support students' reading engagement, specifically by offering their students choice, providing effective scaffolding and individualized feedback, providing authentic learning opportunities, and implementing thematic units. Generating effective student collaboration was also identified as important, but this presented challenges in online and hybrid learning. Secondary English language arts teachers could benefit from additional professional development training in effective constructivist approaches to online instruction as these would further support reading engagement among online students. [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/en-US/products/dissertations/individuals.shtml.]