The assistant secretary of defense for mission capabilities (ASD(MC)) is a position in the United States Department of Defense responsible for the overall supervision of mission capabilities, prototype testing, and the demonstration of "multi-domain" concepts. The officeholder is the principal advisor to the under secretary of defense for research and engineering.
The position was created in 2023, under the leadership of Defense Secretary Lloyd Austin.
In July 2025, President Donald Trump nominated James Caggy to the position.