This article argues that mainstreaming responsible management education in line with the Principles of Responsible Management Education (PRME) requires close attention to the hidden curriculum (HC), that is, the implicit dimensions of educational experiences. Altering formal curricular goals and content alone is not enough to improve students' sense of social responsibility. Business schools are conceptualized in this article as multilevel learning environments comprising various message sites where students undergo moral learning and socialization processes. Using perspectives from HC research combined with transformative learning and communities of practice theory, the article offers an inquiry-based framework for PRME implementation that takes these moral learning and socialization processes into account. It provides suggestions for how to address the hidden curriculum both in the diagnostic phase of assessing a school's PRME needs and in the implementation phase where PRME is integrated into business school learning environments. The concept of "meta-messages" is introduced to account for how students apprehend the HC at business schools. (Contains 6 notes and 2 figures.)