Mobile Security Deployments (MSD) is a small specialized tactical unit within the Diplomatic Security Service (DSS) of the United States Department of State. The MSD provides U.S. embassies and consulates with security support, protects the Secretary of State and other U.S. officials, including domestically as well as visiting foreign officials, and also provides security training at U.S embassies and consulates.

The Diplomatic Security Service (DSS) is the principal security and law enforcement agency of the United States Department of State (DOS). As the operational division of DOS Bureau of Diplomatic Security, its primary mission is to provide security to protect diplomatic assets, personnel, and information, and combat visa and passport fraud. DSS also conducts counterterrorism, counterintelligence, cybersecurity and criminal investigations domestically and abroad.