Robert Ellsworth Gross (May 11, 1897 – September 3, 1961) was an American businessman involved in the field of aviation.

His first venture, the Viking Flying Boat Company, failed with the loss of the aircraft market brought on by the Great Depression.

Gross bet the future of the struggling new company on the (for its time) very advanced all-metal, retractable Model 10, named the Electra.

The Electra placed Lockheed in a strong competitive position, and from 1937 the company mass-produced P-38 Lightning fighters and, from 1943, Constellation airliners, along with numerous other types.

In the 2004 film The Aviator, the character of Robert Gross appeared in a brief scene, played by Brent Spiner.