In 1933, Belfast Corporation decided to install a zoological collection on the site of the Bellevue Gardens on the Antrim Road.
In 1934, 12 acres on either side of the grand floral staircase (a series of steps designed to reach the top of the hillside) were laid out as the zoo site. The zoo was opened on 28 March 1934 by Sir Crawford McCullough, Lord Mayor of Belfast.
During the 1950s and 1960s, the zoo went into decline. By the time the corporation's parks committee took control of the site in 1962, restoration was badly needed and work began on the new zoo site in 1974.
Since then the zoo has become a leading conservation zoo which is respected globally for the work carried out.