Abstract: Mentors on robotics teams have the potential of impacting their students' learning experience. This study used a qualitative approach to examine the roles of mentors and the mentor-student interactions on two high school robotics teams where both teams desired their students to take up leadership roles in designing and building their robot. How were mentors involved in encouraging self-directed learning on their robotics team? How did students behave and respond to their mentors’ involvement? Mentors on one team provided scaffolding to students who showed signs of low engagement or needed help. This led to an increase in overall team participation and student ownership. Mentors on the second team gave students complete freedom to follow their own ideas and provided constant encouragement. Students on the second team displayed characteristics of self-directed learning early in the robotics season but relied more on mentor expertise as deadlines approached.