This study examined the effectiveness of the Exploring Scholars Initiative (ESI) at Alpine International School (AIS) in Europe in enhancing collective teacher efficacy. Established nine years ago, the ESI supports innovation and best practices in professional development. Alpine International School faculty are invited to propose passion projects to grow professionally and develop innovative teaching methods through educational research at Alpine. The ESI at AIS provides staff a unique opportunity to delve deeply into educational issues within their school context by enhancing professional development and enriching the academic environment for all staff and students. The purpose of this study was to interpret and evaluate how a specific model of professional learning (PL) cultivated collective teacher efficacy (CTE) through the identified enabling factors. Twenty Alpine teachers were surveyed and 17 Alpine administrators and teachers were interviewed to answer the following research questions: Q1 How do AIS teachers' experiences with the Exploring Scholars Initiative relate to their measure of collective teacher efficacy?; and Q2 How does the Exploring Scholars Initiative support the five factors of fostering collective teacher efficacy: empowered teachers, embedded reflective practices, cohesive teacher knowledge, goal consensus, and supportive leadership? This study found a correlation between participation in the ESI and higher collective teacher efficacy, particularly in goal consensus, cohesive teacher knowledge, and embedded reflective practices. Implications suggested that while professional learning initiatives enhanced collective efficacy by aligning individual goals with the school's mission and fostering collaboration, structural design and collaborative practices must be optimized to maximize the program's impact across the institution. [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.]