Stortorget (The Big Square) is a small public square in Gamla Stan, the old town in central Stockholm, Sweden. It is the oldest square in Stockholm, the historical centre on which the medieval urban conglomeration gradually came into being. Today, the square is frequented by tens of thousands of tourists annually, and is occasionally the scene for demonstrations and performances. It is traditionally renowned for its annual Christmas market offering traditional handicrafts and food.

Located in the centre of the plateau of Stadsholmen, the square never was the stylish show-piece occupying the centre of many other European cities during the Middle Ages; it was created gradually, buildings and blocks around the square, still sloping west, occasionally added haphazardly. The exception being the Stock Exchange Building taking up the northern side of the square and concealing the Cathedral and the Royal Palace.

Today, Stortorget is the location of the Stock Exchange Building (Börshuset), which houses the Swedish Academy, the Nobel Museum, and the Nobel Library. Designed by Erik Palmstedt and built 1773–1776, it replaced the town hall that had occupied the lot for several hundreds years before and subsequently been relocated first to the Bonde Palace and then to the present Court House in 1915. The plan of the building, French Rococo in style, is a trapezium, the rounded corner of which greatly widened the flanking alleys. While the building is generally designed much like a private palace, the central pediment and the lantern-style cupola crowning the building underline its public status. The closed first floor, accommodating the Swedish Academy, contrasts the openness of the ground floor - a contrast enhanced during the restoration in the 1980s.