In response to Section I299I of the FY21 National Defense Authorization Act, the National Academies of Sciences, Engineering, and Medicine (National Academies) is conducting a series of workshops to discuss current and future issues in preventing, deterring, and countering biological terrorism, particularly focusing on efforts involving the U.S. Department of Defense. These workshops will build on lessons learned from previously-conducted studies and from relevant issues highlighted during the SARS-CoV-2 pandemic. The workshops will focus on three main topics: policy and technical capabilities, policy and programmatic gaps, and current and future bioterrorism threats. Each workshop will result in a Proceedings-in-Brief.