Formalized mentorship programs are an important tool for developing qualified STEMM professionals. Despite an increasingly global STEMM workforce there is little research on how the power distance dimension of national culture may influence the initiation of mentoring relationships. This study explored differences in how mentors from cultures with different power distance orientations started their mentoring relationships with talented adolescents in an online talent development program focused on STEMM. Thirteen mentors were interviewed using teleconference software for this qualitative study. Analysis of the interview transcripts involved a combination of structural and hypothesis coding methodologies. National power distance influences the initiation of mentoring, who drives the relationship, and some aspects of mentor–mentee collaboration. Contrary to expectations, the initiation of mentoring in this STEMM-focused program did not rely on building rapport. During the first few months of mentoring, mentors from greater power distance countries more frequently made decisions and less frequently sought mentees’ opinions than mentors from smaller power distance countries. Notably, mentors did not perceive cultural differences as important or topics worthy of discussion, despite being paired with a mentee from a different country and being asked by the program to address how such differences may influence their mentorship. This study highlights a need for effective education about how cultural differences manifest and influence mentorship and collaboration.