Teachers report lacking sufficient knowledge and support for effective management of attention deficit/hyperactivity disorder (ADHD), particularly in urban school settings. The school social worker's role has been identified as apposite for collaboration with teachers in the behavior management of ADHD, but their knowledge has not been previously assessed. Using a mixed-methods research design, this study assessed ADHD knowledge of N = 43 urban elementary school social workers. The survey data revealed that urban school social workers were knowledgeable about ADHD. They also identified a variety of strategies and interventions for addressing ADHD inside and outside of the classroom. Implications for school social work practice highlight school social workers as an invaluable resource for teachers and as critical collaborators and sources of mental health expertise, particularly in under-resourced urban schools. Additional implications for the role of schools of social work and professional associations are discussed.