The Department of Veterans Affairs (VA) has separate clinical structures and care processes for traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD). However, because veterans are returning from the wars in Iraq and Afghanistan with TBI (most frequently mild TBI [mTBI]) and PTSD, the VA needs to evaluate current service delivery systems. We conducted key informant interviews with 40 providers from across the United States who represented separate clinical teams providing specialized TBI or PTSD services. We identified challenges providers perceive in scheduling and engaging patients with co-occurring mTBI and PTSD (mTBI/PTSD) in treatment, determining the etiology of patients' presenting problems, coordinating services, and knowing whether or how to alter standard treatments. We found consensus that patients with mTBI/PTSD often have other morbidities requiring specialized treatment, including pain and sleep disturbance. Another important theme we found was the need for patient and family educational material on mTBI/PTSD or pain and mTBI/PTSD and provider education tailored to provider specialty. Together, findings point to the need for guidance for providers on best practices to assess and treat mTBI/PTSD given available information, a systematic approach toward patient and provider education, and research to build the evidence base for practice.