How does leadership emerge and develop among university STEM faculty working to adopt evidence-based teaching practices? This qualitative case study examines academic departments as sites for instructional change, viewing leadership as an emergent property of the relationships within a social system. The researcher adopted a dual lens of McElroy and Firestone's Knowledge Life Cycle™ (KLC) of organizational learning in combination with social constructionist Relational Leadership Theory (RLT). Following the constructivist tradition of Stake, the case study explores how leadership influence is expressed and experienced by faculty during efforts to validate and integrate new instructional practices. The researcher interviewed four professors (tenured or tenure-track) at a single public R1 institution in the Southeastern United States with a reputation for offering high-quality undergraduate majors in STEM fields. In-depth interviews lasted 30-60 minutes each; transcripts and relevant documents were coded and analyzed using constructivist grounded theory methods. The findings suggest that faculty are integral power holders because instructional authority is shared collegially. Professors informally occupy three of the six roles for executive leaders in knowledge processing as defined by Martin and Marion (2005). Both formal and informal leadership influence is necessary for change efforts to succeed within STEM departments seeking to move to more student-centered instruction. Three key themes emerged from the study data: 1) Faculty participate in the creation of socially constructed understandings of "good teaching" which are transmitted to other faculty members via institutionally sponsored learning communities, workshops, or conversations within departments. 2) Relational influence (leadership) related to teaching flows primarily horizontally (among networked peers), crossing departmental boundaries even when the focus of faculty work remains solely within one department. 3) Macro, meso, and micro effects on leadership and organizational learning are shaped by The University's loosely coupled, collegial power bases at work within its larger bureaucratic structures. This case study contributes to the research literature by analyzing departmental change efforts through the lens of an emergent, complexity-aware leadership theory in combination with an emergent, complexity-aware organizational learning framework. [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.]