Ban Jelačić Square is the central square of the city of Zagreb, Croatia, named after ban Josip Jelačić. The official name is Trg bana Jelačića. The square is colloquially called Jelačić plac.

It is located below Zagreb's old city cores Gradec and Kaptol and directly south of the Dolac Market on the intersection of Ilica from the west, Radićeva Street from the northwest, the small streets Splavnica and Harmica from the north, Bakačeva Street from the northeast, Jurišićeva Street from the east, Praška Street from the southeast and Gajeva Street from the southwest. It is the center of the Zagreb Downtown pedestrian zone.

The square has existed since the 17th century. Its first name was Harmica. The oldest standing building, dating from the 18th century, is situated at 1 Ban Jelačić Square.

In 1848, the square was renamed to its present name. A large statue of ban Josip Jelačić on a horse, created by Austrian sculptor Anton Dominik Fernkorn was installed on 19 October 1866 by Austrian authorities, despite protests from Zagreb councilmen. It also caused unease amongst Hungarians, who see Jelacic as a traitor.

A horsecar line passing through the square's southern side was introduced in 1891. In 1910–11 horses were replaced by electric trams.

In 1946, the square was renamed Trg Republike (Republic Square). Jelačić's statue was removed in 1947 as the new Communist government of Yugoslavia denounced him as a "servant of foreign interests". Antun Bauer, a curator of the Gliptoteka gallery, kept it in the gallery cellar.

After World War II, car traffic through the square intensified. In 1975, the square became a car-free zone.