Contribution: This longitudinal study modeled student leadership growth in a course sequence supporting long-term, large-scale, multidisciplinary projects embedded in faculty research. Students (half from computer science, computational media, electrical engineering, and computer engineering) participated for 1-4 semesters. Background: Project- based learning (PBL) is used widely in higher education. It is used in industry for leadership development, but leadership development in project-based learning (PBL) has not been explored in higher education. A preliminary analysis implied leadership growth through the third semester of participation, but the design did not control for attrition. Research Questions: At the student level, how do leadership role ratings change over multiple semesters of participation? Do first (and second) semester ratings differ by number of semesters students eventually participate? Methodology: The study involved two peer evaluation questions on 1) the degree to which students coordinated the team's work and 2) served as technical/content area leaders. Analysis employed analysis of variance to examine attrition by initial ratings (N = 1045) and multilevel growth modeling to study change over time (N = 585). A strength of using peer evaluations is the large sample size, but a weakness is that the tool was developed for student assessment and not educational research. The study did not control for participation in leadership programs outside the course. Findings: On average, individual leadership role ratings increased each semester through the third semester of participation. Ratings of students who left the program after 1 or 2 semesters did not differ from ratings for those who participated longer.