This study applies the psychological theories of Kohlberg (1969, 1979) and Rest (1986) and explores existing literature that investigates factors affecting the cognitive moral development of accountants (see Jones et al.  for a review of this literature), while advancing discourse regarding the contributing factors of external classroom activities on the development of accounting students' moral growth. Using a sample of 396 undergraduate accounting students from across the United States, we examine the affect that internship experiences, prosocial behavior exhibited through volunteerism, Beta Alpha Psi Honor Society membership, and student government involvement have on their level of ethical development. Our results indicate that undergraduate accounting students who have interned with a public accounting firm, or participated in extracurricular activities involving volunteerism or membership in Beta Alpha Psi, demonstrate higher levels of cognitive moral development. Results with respect to involvement in student government and cognitive moral development are inconclusive, possibly due to the small number of participants who were involved in student government activities. We provide evidence that extracurricular activities have a positive impact on the ethical development of future accountants in that these activities prepare them to enter the industry with integrity, morals, and a solid grasp of professional ethics.