Abstract Objective To compare attitudes toward privacy in with social network sites (SNSs) and moral development between undergraduates nursing and advertising students. Methods Cross-sectional study conducted with 324 nursing students and 209 advertising students selected by convenience sampling method in two universities in South Korea. Data were collected by means of a questionnaire with Likert type responses, and analyzed descriptive and analytical statistics using SPSS. Results The most posted subject and the most regretted post on their SNS was "pictures of myself". There was no difference in attitudes toward privacy in SNSs and moral development between nursing and advertising students. Most of students were observed in stage 3, a conventional level of moral development. At stage 4 and 5-6 in moral development, the percentages of 4th academic year of college and male students were high. Conclusion Attitude toward privacy in SNS and moral development of nursing students need to be promoted from conventional to postconventional level.