Charles Alton Ellis (1876–1949) was a professor, structural engineer and mathematician who was chiefly responsible for the structural design of the Golden Gate Bridge. Because of a dispute with Joseph Strauss, he was not recognized for his work when the bridge opened in 1937. His contributions were ultimately recognized at the bridge with a plaque installed in 2012.

Ellis was born in Parkman, Maine in 1876.

He earned a degree in mathematics from Wesleyan University (where he was a member of Delta Kappa Epsilon fraternity). In 1922, he received his graduate certificate in engineering (C.E.) from the University of Illinois.

Ellis took a post at the American Bridge Company, where he worked on the stresses of subway tunnels crossing the Hudson River. Ellis completed coursework to extend his knowledge of structural engineering at the University of Illinois.

In 1922 he was expert enough to author a benchmark textbook in the field, Essentials in the Theory of Framed Structures.

Ellis began working on the Golden Gate Bridge in 1922, the same year he gained his engineering certificate from University of Illinois. He remained with the project until December 1931. He then opened a consultancy practice in Chicago, working as an advisor to the Public Works Administration.

During his career, he was a professor at the University of Michigan, the University of Illinois, and Purdue University. His papers are held at the Purdue University library.

Ellis was responsible for the structural design of the bridge, working from the overall design by Strauss.