Fort Detrick (pronounced /ˈdi:trɪk/) is a U.S. Army Medical Command installation located in Frederick, Maryland, USA. Historically, Fort Detrick was the center for the United States' biological weapons program (1943-69).

Today, Fort Detrick's 1,200-acre (490 ha) campus supports a multi-governmental community that conducts biomedical research and development, medical material management, global medical communications and the study of foreign plant pathogens. It is home to the U.S. Army Medical Research and Materiel Command (USAMRMC), with its bio-defense agency, the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID). It also hosts the National Cancer Institute-Frederick (NCI-Frederick) and will be home to the planned National Interagency Biodefense Campus.

Fort Detrick is the largest employer in Frederick County, Maryland.