Background: Designed in 2012 with a first implementation in 2013, NE STEM 4U is a professional development program for post-secondary students/undergraduates, and serves as a source of outreach, content knowledge generation, and STEM literacy for youth in grades kindergarten through 8th grade (ages 5-14). The model empowers post-secondary students as facilitators of inquiry-based learning within the context of an out-of-school time program. This study investigated the potential for replicating or 'franchising' this model by evaluating on the following: (1) Is the model replicable?; and, if so; (2) what core elements are necessary for program fidelity?; and (3) is there a dependency on a particular setting/participant type (e.g., a more rural or urban setting)?Results: Strategic expansion of the program to different institutional types (i.e., Research 1, Research II, and a predominantly undergraduate institution), different geographical locations (i.e., rural and urban), and with various school district partners (i.e., large and small) determined that program fidelity and replicability required 4 core elements or criteria: (1) intentional programming; (2) staff quality; (3) effective partnerships; and (4) program evaluation and continuous improvement. Importantly, we examined emergent themes by each site, as well as in combination (n = 16 focus group participants, n = 12 reflection surveys). These data indicated that "Flexibility" (21.22%), "Student Engagement (i.e., Youth)" (19.53%), "Classroom Management (i.e., also pertaining to youth)" (19.31%), and "Communication" (15.71%) were the themes most referenced by the post-secondary student mentors in the NE STEM 4U program, regardless of site. Finally, the YPQA results demonstrate general replication of program quality in a "franchise" location. Conclusions: These results highlight the core elements of the NE STEM 4U program for consideration of expansion (through strategic replication or 'franchising') as a possible international model. The findings and voices highlight the program's trajectory toward success into environments that expand professional development for post-secondary students, and for delivering STEM opportunities for youth.