Ralph Modjeski (born Rudolf Modrzejewski; Polish: [mɔˈdʐɛjɛfskʲi]; January 27, 1861 – June 26, 1940) was a Polish-American civil engineer who achieved prominence as "America's greatest bridge builder."

In July 1876, they emigrated to America, where, as a matter of convenience, the boy's mother changed her name to Helena Modjeska and her son's name to Ralph Modjeski.

The son returned to Europe to study at l'Ecole des Ponts et Chaussées (the School of Bridges and Roads) in Paris, France.

After completing his academic training, Modjeski returned to America to begin his career, working first under the "father of American bridge-building," George S. Morison.

[2] Modjeski's first project as chief engineer was the railroad bridge across the Mississippi River at Rock Island, Illinois.