Traumatic brain injury (TBI) disproportionately affects marginalized populations social workers serve. Current practices and training needs of social workers who serve clients with TBI are not well-understood. An online survey was administered to all licensed social workers in Washington (N=5,032) to assess the following for clients with TBI: interactions, challenges, knowledge, beliefs, confidence, and training recommendations. Analyses involved descriptive statistics, logistic regression, and content analysis of open-ended responses. Respondents (n=834, 16.6% response rate) endorsed serving clients with TBI, heterogeneous confidence and practices, limited training, and high learning needs. New training approaches are needed to prepare social workers to better provide services to these clients. Training on diagnosis, understanding comorbidities, treating behavioral symptoms, disparities, and advocacy tools are recommended.