In recent years, expectations for schools have increased to the point where they are now expected to ensure that "all" students are learning at high levels. This is a daunting, complex, and ambitious aspiration that requires leadership beyond that provided by the principal. The purpose of this qualitative study was to analyze teachers' perception of principal practices that positively or negatively influence distributed leadership in a school, as well as teachers' perceptions of the benefits and drawbacks of such efforts. In doing so, this researcher will improve ways in which a principal can best support a distributed leadership model. The study focused on the perspectives of 57 middle school teachers from one suburban school district in Central Massachusetts. Data collection involved the following components: a) An anonymous online questionnaire to obtain information regarding teachers' perceptions of distributed leadership and a principal's influence on distributed leadership in a school, b) A series of three focus groups, heterogeneously grouped to represent a cross-section of teachers and specialists, discussing participants' personal experiences in the context of distributed leadership. c) Reflective note-taking to assist with recall of group dynamics and information shared. These data were thematically coded and analyzed in order to identify principal practices that positively or negatively influenced distributed leadership in a school, along with the benefits and drawbacks of such efforts. The findings provide teachers' perceptions of principal practices that support distributed leadership. Results of the study are relevant to principals and school leaders who seek to better understand what a principal does (or does not do) to influence distributed leadership in a school, while considering the benefits and drawbacks of these efforts. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]