This qualitative, phenomenological study explored the impact self-efficacy had upon 13 elementary public-school teachers and their abilities to deliver effective online instruction using instructional technology during the shift to remote teaching following the COVID-19 pandemic school closures within Allegheny County, Pennsylvania. The social constructivist theory served as the conceptual framework for this study as the researcher sought to understand the world within which the study participants lived and worked (Creswell and Creswell, 2018) when schools closed from March through June 2020. Data for the study was collected from participants using a semi-structured interview process. As part of the phenomenological data analysis process (Creswell and Poth, 2018), open coding (Saldana, 2016) was utilized which led to the emergence of key themes within the participants' interview responses. Within the findings of the study, participants reported that factors such as professional and personal experiences with technology, feelings and dispositions, access to instructional technology resources, and the types and focal points of professional development experiences prior to and during the COVID-19 school closure, varied significantly and directly impacted their self-efficacy and perceived effectiveness with regards to using instructional technology to teach online. Based upon the findings, the researcher proposed applications to theory and practice, presented impacts on leadership, suggested implications for policy and practice, and offered recommendations for future research. [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.]