The pursuit of weapons of mass destruction (WMD) and potential use by actors of concern pose a threat to U.S. national security and peace and stability around the world. Adversaries may use WMD to threaten or carry out attacks on the United States, our forces at home or abroad, or our allies and partners. Our political will and military capability to provide security, resist co-ercion, and defeat aggression must not be undermined by WMD. This document, the Department of Defense Strategy for Countering Weapons of Mass Destruc-tion, represents the Department of Defense's response to the WMD threat. It specifies desired end states, prescribes priority objectives, delineates a strategic approach for achieving those ob-jectives, and outlines the countering WMD activities and tasks necessary for success. In a constrained fiscal environment, we are focusing our efforts on preventing acquisition and countering the most likely threats. Accordingly, this strategy emphasizes early action through pathway defeat, shaping the environment to dissuade actors from pursuing WMD, and cooper-ating with partners to achieve countering WMD goals. We are prioritizing capabilities that counter operationally significant risks and activities that are best executed by the Department rather than by partners in the U.S. Government or the international community. This strategy provides foundational guidance for enacting the Department's countering WMD policies, plans, and programs and advances a comprehensive response to existing and developing WMD threats.