Scholars and researchers demonstrate that principals substantially influence the quality of professional learning and offer various perspectives on the principal's role in professional development (Bredeson, 2003; Bredeson & Johansson, 2000; Kose, in press; Lindstrom & Speck, 2004; Tallerico, 2005; Youngs & King, 2002). However, how high school principals create professional development opportunities to improve teachers' ability to prepare diverse students for postsecondary education and justice-oriented citizenship is inadequately understood. This study examines peer-nominated high school principals' espoused practices in teacher professional development. In particular, it seeks to uncover their promising practices of supporting teacher learning that are ultimately aimed at simultaneously preparing diverse students for postsecondary education and as future justice-oriented citizens. One research question guided this inquiry: How do peer-nominated high school principals describe their practices in teacher learning for developing diverse students' college cultural capital and justice-oriented citizenship? After reviewing literature on college cultural capital, citizenship, teaching diverse students, and the principal's role in teacher learning, this article describes the data collection and analysis methods and presents the findings and their implications for practice and research.