Johnson Square is one of the 22 squares of Savannah, Georgia, United States. Located in the northernmost row of the city's five rows of squares, it was the first of the squares to be laid out, in 1733, and remains the largest of the 22. It is east of Ellis Square, west of Reynolds Square and north of Wright Square. Situated on Bull Street and St. Julian Street, it is named for Robert Johnson, colonial governor of South Carolina and a friend of General James Oglethorpe. The oldest building on the square is the Ann Hamilton House, at 26 East Bryan Street, which dates to 1824.

The city of Savannah, Province of Georgia, was laid out in 1733, in what was colonial America, around four open squares, each surrounded by four residential "tithing") blocks and four civic ("trust") blocks. The layout of a square and eight surrounding blocks was known as a "ward." The original plan was part of a larger regional plan that included gardens, farms, and "outlying villages." Once the four wards were developed in the mid-1730s, two additional wards were laid. Oglethorpe's agrarian balance was abandoned after the Georgia Trustee period. Additional squares were added during the late 18th and 19th centuries, and by 1851 there were 24 squares in the city. In the 20th century, three of the squares were demolished or altered beyond recognition, leaving 21. In 2010, one of the three "lost" squares, Ellis, was reclaimed, bringing the total to today's 22.