The purpose of this qualitative study was to understand Indiana High School principals' perceptions and practices of cultural competence in their schools. The projected changes in the demographics of the United States (US) school age population will result in traditionally underserved ethnic minority students being the majority in US schools in the next few years. Despite the billions of dollars that have been spent to close the achievement gap (TAG) between Whites and traditionally underserved ethnic minority students, TAG persists. Scholars have proposed that cultural dissonance, incompatibilities between a school's culture and that of its students, may be a reason for TAG. As a result, cultural competence may be a vehicle that institutions can use to reduce cultural dissonance and close TAG. This study used a phenomenological framework and utilized semi-structured interviews to obtain data from 10 Indiana High School Principals whose schools had at least a 40% traditionally underserved ethnic minority population. The data were analyzed using Lindsey et al's (2009) "5 Essential Elements of Cultural Proficiency" as well as 15 indicators of cultural competence that were gleaned from their research. Open coding was conducted using a framework described by Tesch (1990) to identify emergent themes from the principals' commentaries. Results showed that principals demonstrated high proficiencies in assessing their cultures, valuing diversity, and adapting to diversity within their institutions. Growth, however, is required in their abilities to manage the dynamics of difference within their institutions and their propensity for institutionalizing cultural knowledge. In this study, four themes emerged from the interviews that principals found to be central to their perceptions and practices of cultural competence, they are: (a) having a strong mission and vision, (b) providing platforms for students to showcase their cultures, (c) developing a culture of intentionality, and (d) having a strong data culture. Additionally, three assertions were evident from the interviews: (1) principals should construct a mission and vision with all students in mind and the contents of the mission and vision should be created by an advisory group whose demographics are representative of the institution, (2) a fundamental part of building a culture of intentionality is avoiding assumptions, and (3) principals need to develop a systematic way of gathering, analyzing and making decisions from the data they gather. These themes and assertions could prove useful to principals who are looking to use cultural competence to affect change within their institutions. [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.]