Philadelphia, Pennsylvania, the sixth-most populous city in the United States of America (as of 2020), has many Oz connections.

Oz-connected people in the real world, who were born and/or lived in Philadelphia, include W.W. Denslow, Walt McDougall, Maxfield Parrish, John R. Neill, Frank Moore, William F. Lee, Joseph Breen, Ruth Plumly Thompson, Norman Sherrerd, Eleanor Boardman, Sidney Lumet, and Charles Santore.

McDougall was a prominent political cartoonist for The Philadelphia North American, one of the newspapers that featured the syndicated strip. The artist was reportedly arrested on a monthly basis for libel; local politicians are said to have offered him $1500 to leave the city during the 1904 presidential election.

Thompson was writing children's material for a local newspaper, The Philadelphia Public Ledger, when William Lee recruited her to write Oz.

Fictional characters Button-Bright, Peter Brown, Notta Bit More, Bobby Downs, David B. Perry, and their immediate families, are all from Philadelphia or at least the general Philadelphia area.

In Who's Who in Oz, Jack Snow incorrectly adds Speedy to the list of Ozian boy heroes from Philadelphia. In fact, Speedy is from Long Island.