David N. Miller Jr. (born c. 1971) is a United States Space Force major general who serves as the director of operations, training, and force development of the United States Space Command. Previously, he was as the Assistant Deputy Chief of Space Operations for Operations, Cyber and Nuclear and, prior to that, the senior military assistant to the United States Secretary of the Air Force. In April 2021, Miller was nominated for transfer to the United States Space Force and promotion to major general.