Williamstown Lighthouse, Maritime navigation site in Point Gellibrand, Australia

Williamstown Lighthouse is a square bluestone tower at Point Gellibrand, Williamstown, Victoria. Built in 1852 to a design by Henry Ginn, it stands 17 metres high on ground 22 metres above sea level. Its lower storeys have battered, rusticated masonry with smooth string courses, and a castellated parapet carries a mast with a spherical copper timeball.

The site began with a wooden structure in 1840 and was later replaced by the current bluestone tower, which served ships until 1987. The construction reflected how British colonial authorities built maritime infrastructure along Victoria's coast.

The tower's name comes from the copper timeball that crowned its mast: each afternoon it was hoisted and dropped at exactly one o'clock so ships offshore could check their chronometers. A second signal was given at eight each night by eclipsing the lantern. The ball was dismantled in 1926 and reinstated after 1989.

The timeball was dismantled in 1926 and later reinstated after the brick tower added in 1932 was removed in 1989, so it no longer drops at one o'clock. The square bluestone tower stands 17 metres high on Point Gellibrand, at an elevation of 22 metres, and can be viewed from outside at any hour.

The timeball was a copper sphere that encircled the central mast and rested in an iron catcher cup when not in use. Each afternoon it was raised and dropped at exactly one o'clock so ships' captains offshore could check their marine chronometers. The tower gave a second signal at eight each night by eclipsing its lantern.