The Washington Square Players (WSP) was a theatre troupe and production company that existed from 1915 to 1918 in Manhattan, New York City. It started as a semi-amateur Little Theatre then matured into a Repertory theatre with its own touring company and drama school. It received national newspaper coverage and sparked like-minded companies across the country. After it ceased operating, three of its members founded the Theatre Guild.

The Theatre Guild is a theatrical society founded in New York City in 1918 by Lawrence Langner, Philip Moeller, Helen Westley and Theresa Helburn. Langner's wife, Armina Marshall, then served as a co-director. It evolved out of the work of the Washington Square Players.