Postdoctoral training provides an opportunity to solidify diversity and social justice-related competencies before independent practice. This training period is an excellent time to integrate knowledge and skills into professional identity and practice, including translating social justice theory into advocacy and other aspects of practice. Effectively assessing training needs and tailoring curriculum for a professionally and personally diverse fellowship cohort is difficult. This article presents 2 interrelated studies that aim to capture diversity and social justice training needs at the postdoctoral level. First, we conducted a scoping study of associated literature, resulting in development of a new self-assessment to identify gaps in social justice training. Second, we piloted this self-assessment among incoming psychology postdoctoral fellows in an American Psychological Association accredited program. Findings from each of these studies were broadly congruent, indicating that although training programs and incoming fellows are invested in diversity and social justice training, there are notable and consistent gaps in training. We offer a set of recommendations to improve diversity and social justice training among incoming fellows including continued use of the piloted assessment in research and training; identification of a best practices training model; increased prioritization of social justice advocacy training experiences and other active training approaches; and intentional cultivation of ‘safe brave’spaces to facilitate effective discussions about diversity and social justice topics.(PsycInfo Database Record (c) 2020 APA, all rights reserved)