The purpose of this study was to examine the perceptions of high school principals? regarding the impact of a high stakes accountability system on instructional practices. The study assessed the differences in perception and influencing factors about the impact of a high stakes accountability system between and among high school principals based on campus ratings and selected demographic variables. The data for this quantitative study were obtained from a 59-question survey instrument given to high school principals from 37 school districts selected from Region I of the Texas Education Service Center and 42 school districts selected from Region XX of the Texas Education Service Center. The researcher collected 92 completed surveys, or 72% of the sample. An analysis of the data found that high school principals did indicate perceived changes to some instructional practices. The data showed a perceived increase in the use of problem-solving activities, open response questions, writing assignments, creative/critical thinking questions, peer or cross-age tutoring, interdisciplinary instruction, facilitating/coaching, collaborative/team-teaching, modeling, cooperative learning/group work, computers/educational software, calculators, computers, internet and/or on-line research service, lab equipment, and manipulatives. Principals also indicated a perceived decrease in the use of work sheets, true-false questions; textbook based assignments, lecturing, and the use of textbooks. In addition, the data showed that high school principals' perceived changes to instructional practices were influenced most by two factors: an "interest in avoiding sanctions at my school," and an "interest in helping my students attain TAKS scores that will allow them to graduate." The information obtained from this study can be used by researchers, educators and all stakeholders to ensure implementation of instructional practices leading to student achievement on high-stakes tests.