This case study analyzes the ethical training methods of the United States Marine Corps (USMC) and explores their potential application to building ethical corporate cultures. The USMC trains a large number of recruits annually in ethical conduct and operates under highly stressful conditions, often perceived as moral exemplars. The study investigates the recruit training practices at Parris Island, SC, and suggests applications consistent with ethical and psychological research. Key lessons include selecting values that fit the business, fostering trustworthy leadership, and implementing strategies for ethical socialization, emotional control, and realistic simulation. The analysis aims to provide insights into how organizations can improve ethical behavior by adopting principles from the USMC's rigorous training program.