This study questions the widely held assumption, particularly in the United States, that coeducation is best. Previous research supports the development of single-sex education for both female and male students. This study examines how the learning climate of the coeducation environment seems to affect the character development of female business students. Female business students from 11 single-sex colleges (secular and religious) perceived more reinforcement in 13 of 21 character traits than female (and male) students in 3 coeducational institutions. Several of these character traits are related to ethical behavior, such as honesty, compassion, and independence, and are sorely needed in the workplace. Improved ethics education may enable women to play a larger role in avoiding future ethical crises. (Contains 1 figure, 3 tables, and 2 notes.)