Waning student engagement over the course of year-long capstone design projects may decrease team effectiveness and create challenges for capstone faculty advisors and student team leaders. Because leadership is an influence process, reframing how leadership is conceptualized for students may provide a tool that can bolster student effort and overall team effectiveness. Recent literature suggests that sharing leadership may be more effective than vertical leadership for complex design work, but little is known regarding shared leadership within the undergraduate engineering context. This study examined the relationship between shared leadership and team effectiveness for undergraduate mechanical engineering capstone design teams using an adaptation of the Full Range of Leadership model. Results indicated that the overall strength and a limited sharing of select team leadership behaviors relate to a team’s effectiveness through group process and individual satisfaction, but not task performance. This study provides capstone faculty with insights into effective leadership behaviors that may be encouraged within the capstone design experience