The purpose of this exploratory study was to analyze how high school principals approached developing a collaborative culture and providing collaborative leadership in a large high school setting. The population sample for this study was 82 principals of large comprehensive high schools of grades 9 through 12 or some combination thereof with student populations of more than 1700 students from nine states in the middle region of the United States including Colorado, Missouri, Kansas, Iowa, Nebraska, Illinois, Indiana, Oklahoma, and Wisconsin. Of the 82 respondents, 81 fully completed the survey and one was incomplete. The survey was developed from questions from several survey instruments by Dr. Jeffrey Glanz, Professor, Yeshiva University, Dr. Jerry Valentine, Professor Emeritus at University of Missouri, Dr. Hank Rubin, Professor at South Dakota State University, and the researcher. Quantitative data examined beliefs, practices, and self assessments by the principal based on collaborative leadership, collaborative learning, and school culture. Inferential statistics were used to draw conclusions from the sample population tested. The study through an analysis of variance and bivariate correlations analyzed differences sorted by degree of collaboration and relationships among variables correlated with collaborative learning and leadership of principals in a large high school setting. In addition, demographic data were analyzed using ANOVA to test for correlations between these interrelated variables of the degree of collaborative learning in the school as described by the schools' principals (a) the degree to which the principals' self-described their leadership practices, (b) the degree to which the principals' self-described their beliefs about collaborative leadership, and (c) the demographic characteristics of the principals' professional experiences and background. The study found principals in large high schools their learning practices, their beliefs about collaborative leadership, examples of their work, and their perceptions about the degree of collaborative learning were evident. The study found there are significant differences in leadership practices and beliefs for schools that are perceived as more collaborative compared to those perceived as less collaborative. The study found, however, there was no significant relationship between demographic characteristics of professional experiences and background were related to collaborative leadership and learning practices and beliefs. Overall, the findings from this study created awareness about the uniqueness of collaborative leadership in a large high school setting and how principals of large high schools can more readily facilitate collaborative learning in these complex settings. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]