School principals are responsible for improving low College and Career Ready Performance Index (CCRPI) scores; however, little was understood about how K-12 school principals' leadership practices were perceived to improve CCRPI scores in schools. The purpose of this basic qualitative study was to examine the leadership practices of K-12 school principals to increase CCRPI scores in a Title I school district in the southeastern United States. The research question addressed the leadership practices of K-12 school principals that were intended to increase CCRPI scores in their Title I school district. The conceptual framework was the instructional leadership framework of Hallinger and Murphy, which describes the activities, functions, and processes for instructional leadership. Data were collected via semistructured interviews with eight principals of schools that had an overall CCRPI score below 70. Data were analyzed inductively using open and axial codes plus thematic analysis. Themes regarding leadership practices of K-12 school principals that are intended to increase CCRPI scores include (a) CCRPI score and accountability efficacy, (b) collaboration and communication, (c) data driven decision making, and (d) supporting teachers. The findings may contribute to positive social change because increased understanding of these leadership practices for CCRPI scores may lead to higher graduation rates as well as increased college and career readiness for students. [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.]