The Department of Defense (DOD) spends hundreds of billions of dollars annually acquiring products and services. Since 1990, Congress and DOD have taken numerous steps to address issues related to the quality of DOD's acquisition workforce, which consists of contracting officers, cost estimators, and personnel in several other career fields. But tens of thousands of others, referred to as nonacquisition personnel, also affect how DOD acquires products and services such as major weapon systems and logistics support. These personnel have a wide range of primary responsibilities, such as piloting aircraft and managing facilities, and they are sometimes directed to perform acquisition-related functions, such as overseeing contracts. The National Defense Authorization Act for Fiscal Year 2018 included a provision for the Government Accountability Office (GAO) to review steps DOD has taken to ensure non-acquisition personnel receive appropriate acquisition-related training. This report addresses the extent to which DOD can identify (1) non-acquisition personnel supporting acquisitions, and (2) their need for acquisition training. GAO analyzed training data; reviewed policies, guidance, and memorandums; and interviewed personnel from the Office of the Secretary of Defense and the military departments. [This report was revised on October 2, 2019 to correct two numbers that had been transposed in the Highlights page figure.]