New teachers in the US often are unprepared to meet the needs of culturally and linguistically diverse students. Preparing teachers for diversity has generated widespread interest in mentoring, yet little research has explored a knowledge base for equity-focused mentoring. Drawing on expertise of leading mentor practitioners and a case study, this article builds a framework for what mentors need to know and be able to do to focus new teachers on equity. Mentors need a bi-level and multi-domain knowledge base, targeting both students and teachers. Using a bifocal perspective, mentors view the new teacher up close, but also focus on the larger picture of students. Analyses delineate challenges and tensions in tapping this knowledge base in the action of mentoring.