The movement for multicultural or diversity-centered education has resulted in changes to the academic demography of the United States. Institutions of higher education have integrated the voices, knowledge, and lived experiences of various underrepresented cultures and excluded groups into their formal academic curriculum. A recent survey by the American Association of Colleges and Universities (AACU) shows that 63% of colleges and universities report that they have in place, or are in the process of developing, a diversity education component in their undergraduate curriculum. The success of many colleges and universities at integrating this level of multicultural or diversity education into the academic curriculum marks a significant higher education milestone. However, an organized and entrenched resistance to this movement has emerged at both individual and organizational levels. The diversity-education classroom, in particular, is a site wherein this conflict takes on particular meaning for instructors of color (that is, faculty members or graduate student instructors who identify or are identified as "non-white") at all academic ranks. This study is part of a larger investigation into the professional, emotional, and physical labor associated with teaching diversity-education courses in higher education. The authors argue that the experiences of instructors of color intertwine with campus efforts to recruit and retain minority instructors in higher education and should raise questions about the role of the required diversity course, its structure, process, and outcomes. In this paper, the authors explore key themes from in-depth interviews with 20 instructors of color who teach required diversity courses at a predominately white college or university (PWCU) in the Midwest. From these responses, the authors identify central challenges for instructors of color. They focus on how instructors of color engage their own agency in the face of student resistance, and the countermeasures they craft to maintain their credibility and intellectual authority in the diversity classroom. (Contains 1 table.)