In cyber charter schools, middle-school students face many barriers to developing STEM identity. My theory of improvement was to address sense of belonging in a large virtual classroom to develop STEM identity in my students. By utilizing diverse STEM role models that reflected my students' racial or ethnic identities and an inquiry-based approach to teaching, my intervention nurtured the development of STEM identity in my online students. This intervention addressed both STEM identity and sense of belonging by encouraging students in underrepresented groups to participate and engage with STEM professionals who look like them in synchronous class sessions. This study shows promise for reducing the barriers to developing STEM identity online because the intervention can foster community and a sense of belonging in the virtual classroom while also teaching about STEM careers, diversity, and inclusion. [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.]