Nearly half of new teachers leave the profession within five years of employment, and most would not recommend teaching as a profession. A shortage of highly effective teachers continues in public schools across the nation; hence, meaningful professional development needs to be implemented to adequately prepare and retain teachers for the classroom, and this need is further compounded in the online setting. The goal of this study was to ascertain school leaders' and teachers' perceptions of preparedness for an online K-12 school by examining perceptions of preparedness in three categories: student learning and engagement, curriculum and instruction, and data-driven decision-making. Findings from this study indicated that school leaders and teachers did not perceive teachers as being adequately prepared for the K-12 online setting. Future research should aim to identify the implementation of purposeful, collaborative, and sustainable professional development based on needs and identified trends in online K-12 schools to ensure teachers are prepared for the online setting.