The authors introduce the Preparation in STEM Leadership Program at Rutgers, The State University of New Jersey. This NSF-Funded program and research study creates a centralized training program for peer leaders that includes a battery of assessments to evaluate peer leaders' content knowledge, pedagogical knowledge, communication skills, and leadership practices over time. This article introduces readers to the program and its theoretical background, explains some lessons learned regarding the program design and implementation, and briefly describes preliminary findings on a broad-scale from peer leaders' assessments intended to measure skills and content development.