This study examined the effects of a school improvement project involving Distributed leadership (DL), a perspective for studying or developing organization leadership through the interaction of organizational members and activities. This research was part of a larger DL Project taking place in York City School District, PA, which sought to improve school leadership to enhance student achievement as a final end. While recent studies provided significant findings about DL's contribution to school improvement, the literature begs for more research about the effects of distributed leadership. One of the effects the DL Project wished to accomplish was the development of trust among the DL teams. According to the literature, trust has a direct link to academic achievement and school improvement respectively. Similarly, it was expected that this effect would improve the implementation of the DL Project. This smaller study sought to answer how, if at all, the DL Project implementation changed trust on the teams and in the schools; and how the experience of doing an evidence-based project, within the DL Project, contributed to the changes in trust in the teams over time. The two-month study took place in York City schools and involved the first-year of the DL Project, and as participants, DL team members and members from the staff. An embedded mixed methods approach was used to collect and analyze qualitative and quantitative data from project archives, surveys and interviews. The analysis suggests that trust changed positively or negatively within the first year of the Distributed Leadership (DL) intervention; The DL Project mainly improved respect and integrity (two dimension of trust) among the teams and in the school; The other two dimensions of trust were highly affected during the first year of the DL Project implementation: Competence and personal regard; Improvements in trust are less evident in the first year; The context can greatly affect trust changes; and the evidence-based project proved to catalyze changes in trust during the first year. [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.]