Washington Square is one of the 22 squares of Savannah, Georgia, United States. It is located in the northernmost row of the city's five rows of squares, on Houston Street and East St. Julian Street. It is east of Warren Square and north of Greene Square in the northeastern corner of the city's grid of squares, in Savannah's Old Fort neighborhood. The oldest building original to the square is 510 East St. Julian Street, which dates to 1797.

Built in 1790, Washington Square was named in 1791 for George Washington, the first president of the United States, who visited Savannah that year. It was one of only two squares named to honor a then-living person, Troup Square being the other.

Washington Square had been the site of the Trustees' Garden. Named for the trustees of General James Oglethorpe's colony, the garden was the testing ground for a variety of experimental crops – including mulberry (for silkworms), hemp, and indigo – viewed as potential cash crops. Most of these experiments proved unsuccessful.

The square was once the site of massive New Year's Eve bonfires; these were discontinued in the 1950s.