Aligning the Governance Structure of the NNSA Laboratories to Meet 21st Century National Security Challenges is an independent assessment regarding the transition of the National Nuclear Security Administration (NNSA) laboratories - Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Sandia National Laboratories - to multiagency, federally funded research and development centers with direct sustainment and sponsorship by multiple national security agencies. This report makes recommendations for the governance of NNSA laboratories to better align with the evolving national security landscape and the laboratories’ increasing engagement with the other national security agencies, while simultaneously encouraging the best technical solutions to national problems from the entire range of national security establishments. According to this report, the Department of Energy should remain the sole sponsor of the NNSA laboratories as federally funded research and development centers. The NNSA laboratories will remain a critically important resource to meet U.S. national security needs for many decades to come. The recommendations of Aligning the Governance Structure of the NNSA Laboratories to Meet 21st Century National Security Challenges will improve the governance of the laboratories and strengthen their strategic relationship with the non-DOE national security agencies.