Multi-tiered systems of support (MTSS) have been increasingly implemented in schools since the re-authorization of the Individuals with Disabilities Act of 2004 and the Every Student Succeeds Act (ESSA) of 2015. Despite researchers' efforts to identify elements of MTSS--including evidence-based practices, leadership and communication systems and structures to address learning needs-- it has been challenging to identify what makes MTSS work in schools. In fact, researchers have found that schools who implement MTSS on their own tend to stray from the intended practices when the external support of coaches or research teams fades from the school (Balu, Zhu, Doolittle, Schiller, Jenkins, & Gersten, 2015). The school-based leadership team is often the vehicle for developing, installing, implementing, and sustaining new initiatives, including efforts toward building MTSS (Coyne, Oldham, Leonard, Burns, & Gage, 2016). This study seeks to examine 33 elementary school leadership teams as they develop and implement their school wide reading model with MTSS framework as part of a state-wide reading improvement initiative. School leadership teams engaged the Reading Tiered Fidelity Inventory to self-assess resources, implementation, evaluation, and teaming practices in their school-wide reading model with MTSS framework. The present study seeks to examine the correlation between teaming practices and systems and overall fidelity of implementation of the school-wide reading model across elementary schools implementing an MTSS framework for reading. [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.]