As a result of the COVID-19 epidemic, public school educators encountered several difficulties acquiring and integrating curriculum online. The problem addressed in this study was the negative effect online curriculum implementation had on student achievement as a result of the COVID-19 pandemic. The purpose of this qualitative, exploratory case study was to examine teachers' perceptions of the efficacy of implementing online curricula during the COVID-19 pandemic. Qualitative data regarding the lived experiences of the 25 educators were collected using a case study methodology. Teachers from seventh through twelfth grades participated in the study. Participants were interviewed individually using semi structured questions. There was also a focus group interview consisting of five teacher participants. A member check was used to verify the accuracy of the transcriptions, and NVivo was used to analyze the interviews thematically. Fifteen themes were identified: hindrances to online learning, technology that enhanced the delivery of online curriculum, the impact on the virtual learning environment, high student engagement, high achieving students, negative perceptions of student's cognitive flexibility, negative perceptions of administrative support, positive teacher perceptions of administrative support, technology resources, administrative training, student emotional support, teacher emotional support, student accountability, parental support, and preparation for online learning. Secondary educators felt that the transition to online could have been significantly more efficient, according to the study. Educators, however, were able to use innovative technology to engage students and demonstrate cognitive flexibility to meet students' needs by demonstrating student-centered engagement. [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.]