Charles Oscar Pfeil (9 April 1871 – 2 December 1927) was an American architect and golfer, primarily based in Memphis, Tennessee (USA), during the first third of the twentieth century.

Pfeil was of German descent, and born in Jacksonville, Illinois, in April 1871 on a farm, one of eleven children.

[1] In subsequent years Pfeil worked for various architectural firms in Peoria, Chicago, and St. Louis before moving to Memphis in 1903.

He formed a partnership with George M. Shaw, with whom he designed the Tennessee Trust Building (1906), later the Union & Planters Bank, and since 2002 the Madison Hotel.

[4] Pfeil's other work included the William R. Moore Dry Goods Company and an addition to the rebuilt 1899 Gayoso Hotel.

[5] On this project he apparently collaborated with Professor Newton Alonzo Wells at the University of Illinois for the lobby's mural decorations, which one source called Memphis's "only real works of public art.

His papers, including some from his partnership with Pfeil, are now part of the Awsumb Architectural Collection of the Memphis Municipal Libraries.