This study analyzes mentor teachers' perceptions of culturally relevant pedagogy (CRP) professional development in STEM informal learning spaces and the support needed to nurture practices of CRP. Additionally, the study investigates culturally relevant professional development's (CRPD) influence on mentor teachers' transference of CRP theory into practice to advance racial and gender equity through an informal cybersecurity camp. The qualitative data analysis (semi-structured interviews) provides an overview of the Fall 2022 session of a year-long multi-state virtual cybersecurity camp funded through the Defense STEM Education Consortium Grant #XXX. Participants with work experience in informal STEM camps were recruited from the East and West Coast locations of the United States through an online application process. The data sample is composed of 10 ethnically diverse participants consisting of undergraduate, graduate, in-service teachers, professors, and industry professionals. Findings reveal that multiple and comprehensive CRPD sessions elucidated mentor-teacher interpretation of CRP and the implementation of CRP practices. Future research on CRPD in STEM informal learning spaces is briefly discussed.