Thomsons Lake Nature Reserve is a lake nature reserve around Thomsons Lake in the City of Cockburn, Western Australia, approximately 25 kilometres (16 mi) south of the central business district of Perth, the state capital, and on the southern fringes of the Perth metropolitan area. It is in the suburb of Beeliar, 7 kilometres (4.3 mi) south-west of Jandakot Airport. It is a still largely natural wetland, with adjoining native vegetation, surrounded by land developed for housing and agriculture, that regularly supports large numbers of shorebirds and other waterbirds.

Beeliar is a suburb of Perth, Western Australia, located within the City of Cockburn. The name refers to the Beeliar people, a group of Aboriginal Australians who had land rights over the southern half of Perth's metropolitan area. The suburb contains the Thomsons Lake Nature Reserve.