Harold C. Helgeson (November 13, 1931 – May 28, 2007) was an American scientist and educator.

A pioneering theoretical geochemist, he was a professor at the University of California, Berkeley.

[1] Born in Minneapolis, Minnesota, he grew up in St. Paul.

Helgeson went to Harvard University for graduate school, supervised by Robert M. Garrels.

This biographical article about an American chemist is a stub.