Big Heath Conservation Park (formerly the Big Heath National Park) is a protected area in the Australian state of South Australia located in the gazetted locality of Spence about south-west of Naracoorte in the state's Limestone Coast region.
The conservation park is located on land in sections 17 to 20, 169 and 179, and Allotment 500 in the cadastral unit of the Hundred of Spence. A drain known as "Drain M", which is part of the drainage infrastructure built in the south east of the state since European settlement, passes through the south-east corner of the conservation park, carrying water from Bool Lagoon in the east to the sea at Beachport in the south.
Protected area status began for the land in sections 17 to 20 and 169 on 7 May 1964 when it was constituted under the Crown Lands Act 1929 as a wild life reserve. On 9 November 1967, it was constituted as the Big Heath National Park under the National Parks Act 1966. In 1972, it was constituted as a conservation park upon the proclamation of the National Parks and Wildlife Act 1972 on 27 April 1972. In 1993, section 179 of the Hundred of Spence was added to the conservation park. In 2010, a parcel of land known as Allotment 500 and which was dedicated as a conservation reserve known as the Big Heath Conservation Reserve under the Crown Lands Act 1929 on 9 December 1993 was added to the conservation park. , the conservation park covered an area of .
As of 1994, the conservation park was reported as supporting a "diversity of vegetation types which correlate with the topography and soils of the area" as follows:
As of 1994, visitor use was reported as being "low" and was mainly concerned with "nature study by the local and Naracoorte communities".
The conservation park is classified as an IUCN Category Ia protected area.