Virtual K-12 schools have rapidly become a popular choice for parents and students in the last decade. However, little research has been done on the instructional practices used in virtual courses. As reflected in the central research question, the purpose of this study was to explore how teachers provided instruction for Grade 7-10 students in both English language arts and science courses in a virtual school in a southern state. The conceptual framework was based on Piaget's theory of cognitive development and Garrison, Anderson, and Siemens' research on instructional design. The units of analysis in this qualitative, comparative case study were four virtual courses; the data were collected from teacher and student questionnaires, threaded student discussions, student work samples, and archival records. The first level of data analysis involved coding and categorization using the constant comparative method, and the second level involved examining the data for patterns, themes, and relationships to determine key findings. Results indicated that a standardized virtual course design supported teacher use of direct instruction and summative assessments and some individualized instruction to deliver course content, including adjusting the course pace, conducting individual telephone conferences, and providing small group instruction using Blackboard "Elluminate." Opportunities for student interaction and inquiry learning were limited. This study is expected to contribute to positive social change by providing educators and policymakers with an awareness of the critical need for further study of research-based instructional practices in K-12 virtual courses that would improve student learning. [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.]