Previously, on the site of the square there was a garden with two pavilions — the Picture Gallery and the Opera House, where masquerades and festivals were held in the middle of the 18th century. It was a time of bright and crazy balls, incredible entertainment and dancing all night long. The garden has changed its appearance several times — the influence of changing fashion.

The history of the square began in 1827, when Nicholas I decided to build a theater on the site of the garden, which is now known as Alexandrinsky (in honor of the beloved wife of the emperor). The project was developed by the famous architect Karl Rossi, who conceived the theater as the center of the future square. Under the same project, the Public Library building was enlarged and rebuilt and Teatralnaya Street was built up.

At the end of the 19th century, a monument to Catherine II was erected on the square: the Empress on a high pedestal wearing an ermine robe with a scepter in her hands, and the most prominent figures of that era at her feet. The monument does not cause much enthusiasm among critics, but it fits very well into the architectural ensemble of the palace.

The square has changed its name several times. Initially, in the plan, it was designated as Anichkovskaya, after the construction of the theater - Alexandrinskaya, but in conversations you could often hear Teatralnaya. With the appearance of a monument to Catherine II on the territory of the square, it was renamed into Ekaterininskaya. And, finally, in 1925, it was named Ostrovsky Square in honor of the Russian playwright A. N. Ostrovsky.