Retaining students in the Science, Technology, Engineering, and Mathematics (STEM) fields has been a challenge in the United States (U.S.). More startling is the lack of diversity across most of the STEM disciplines. Underrepresented minority groups majoring and graduating in STEM are reported to be far below the national benchmark, and it is not proportionally reflected in the overall national population. To support students in STEM, New York City College of Technology of the City University of New York has designed a Peer-Led Team Learning Leadership Program (PLTL) that recruits and trains upper freshmen majoring in STEM, particularly those who are underrepresented, to facilitate peer-led workshops in foundational STEM courses in chemistry, civil engineering, and mathematics. Results showed the PLTL Leadership Program to be highly effective for first-year underrepresented minority STEM students. First-year students self-reported the peer leading experience had strongly improved their own understanding of chemistry, engineering, and mathematics concepts, and their confidence in these subject areas was significantly increased. They also indicated gains in their confidence in public speaking and in their leadership, communication, and facilitation skills.