The Thomson Dam is a major Clay core and rockfill embankment dam with a Uncontrolled, Ogee-shaped overflow weir and chute spillway across the Thomson River, located about 130 kilometres (81 mi) east of Melbourne in the West Gippsland region of the Australian state of Victoria. The reservoir created by the dam is officially called Thomson Reservoir, sometimes called Lake Thomson.

The Thomson River, a perennial river of the West Gippsland catchment, is located in the Gippsland region of the Australian state of Victoria.