Frost & Granger was an American architectural partnership from 1898 to 1910 of brothers-in-law Charles Sumner Frost (1856–1931) and Alfred Hoyt Granger (1867–1939). Frost and Granger were known for their designs of train stations and terminals, including the now-demolished Chicago and North Western Terminal, in Chicago. The firm designed several residences in Hyde Park, Illinois, and many other buildings. Several of their buildings are listed on the U.S. National Register of Historic Places.

Charles Sumner Frost was an American architect. He is best known as the architect of Navy Pier and for designing over 100 buildings for the Chicago and North Western Railway.