This dissertation examined the impact of the CREST-MECIS community of practice on K-12 STEM teachers and undergraduate and graduate students, addressing the urgent need for innovative approaches in science education to meet the challenges of the 21st century. The study was grounded in response to three primary problem statements: 1) the significant learning losses and socio-emotional challenges stemming from the COVID-19 pandemic, 2) the inadequacy of traditional instructional methods in post-pandemic classrooms, and 3) the need for culturally relevant and inclusive teaching practices that acknowledge students' lived experiences. Data were collected through pre- and post-interviews, survey analyses, and qualitative feedback from program participants, offering a comprehensive look at the effects of the CREST-MECIS model. The dissertation is organized into several key sections. Chapter One introduces the background and rationale for the study, situating it within the context of post-pandemic educational needs and the theoretical frameworks of culturally relevant pedagogy and constructivist learning. Chapter Two provides a literature review, examining foundational theories by Gloria Ladson-Billings, Lorsbach and Tobin, and Feldman, which advocate for community-based, reflective, and constructivist approaches in education. Chapter Three describes the research methodology, detailing the community of practice model, data collection processes, and participant demographics. Chapter Four presents the study's findings, revealing that participation in CREST-MECIS significantly enhanced students' confidence, motivation, and engagement with STEM subjects and improved teachers' instructional efficacy and attitudes toward culturally relevant and innovative pedagogy. In the final chapter, conclusions were drawn about the program's effectiveness in fostering resilience, inclusivity, and socio-emotional support, aligning with Ladson-Billings' call for a "hard re-set" in education. The study concluded that the CREST-MECIS program offered a replicable model for achieving a transformative shift in STEM education through collaborative, culturally responsive, and experiential learning environments. Recommendations include expanding such programs in diverse educational settings and further exploring the long-term impacts of community of practice models in education. This research contributes to the field by illustrating the potential for a re-imagined STEM curriculum that prepares both educators and students for the complex, interconnected demands of modern society. [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.]