Walter Stuart Diehl (3 December 1893 – 21 November 1976) was an American naval officer and aeronautical engineer.

He was responsible for the funding, programs, and facilities of the Aerodynamics Laboratory.

Diehl initiated action that led to establishment of the David W. Taylor Model Basin at Carderock, Maryland, the Aircraft Research Station at Chincoteague, Virginia, and the U.S. Navy's test flight unit at Naval Air Station Anacostia in Washington, D.C., which later developed into the Naval Air Test Center at Naval Air Station Patuxent River, Maryland.

She was christened in his honor in New Orleans, Louisiana, on 10 October 1987 and entered non-commissioned service as a United States Naval Ship with the Military Sealift Command on 13 September 1988.

This biographical article related to the United States Navy is a stub.