South East Queensland (SEQ) is a bio-geographical, metropolitan and statistical region of the state of Queensland in Australia, with a population of approximately 4.0 million people out of the state's population of 5.5 million. The area covered by South East Queensland varies, depending on the definition of the region, though it tends to include Queensland's three largest cities: the capital city Brisbane; the Gold Coast; and the Sunshine Coast. Its most common use is for political purposes, and covers 35,248 square kilometres (13,609 sq mi) and incorporates 11 local government areas, extending 240 kilometres (150 mi) from Noosa in the north to the Gold Coast and New South Wales border in the south (some sources include Tweed Heads, New South Wales which is contiguous as a conurbation with Brisbane/Gold Coast), and 140 kilometres (87 mi) west to Toowoomba (which is simultaneously considered part of the Darling Downs region). It is the third largest urban area in Australia by population.

South East Queensland was the first part of Queensland to be settled and explored by Europeans. Settlements initially arose in the Brisbane and Ipswich areas with activity by European immigrants spreading in all directions from there. Various industries such as timber cutting and agriculture quickly developed at locations around the region from the 1840s onwards. Transport links have been shaped by the range of terrain found in South East Queensland.

The economy of South East Queensland supports and relies on a wide diversity of agricultural manufacturing industries, commerce and tourism. The region has an integrated public transport system, Translink. The gross domestic product is $170 billion.

The term South East Queensland has no equivalent political representation. The area covers many lower house seats at the federal and state levels. As Queensland has no upper house, there are no Legislative Council provinces or regions to bear the name either.

South Eastern Queensland, as an interim Australian bioregion, comprises 7,804,921 hectares (19,286,380 acres) and includes the Moreton Basin, South Burnett, and the Scenic Rim along with ten other biogeographic subregions. It extends as far north as Gladstone, and south into north-eastern New South Wales.

South East Queensland was home to around 20,000 Aboriginals prior to British occupation. The local tribes of the area were the Yugarapul of the Central Brisbane area; the Yugambeh people whose traditional lands ranged from South of the Logan River, down to the Tweed River and west to the McPherson Ranges; the Quandamooka people whose traditional lands encompassed the Moreton Bay Islands to the mouth of the Brisbane River to Tingalpa and south to the Logan River; and the Gubbi Gubbi people whose traditional lands were known to exist north of the Pine River, to Burrum River in the north, and west to the Conondale Range. According to history researchers the Aboriginal population declined to around 10,000 over the next 60 years.

Early explorers in the area including Matthew Flinders, Allan Cunningham, John Oxley and Patrick Logan. Around 1839, European settlers were able to move into the region. Logging was the first industry to develop. The first railway built in Queensland linked Grandchester to Ipswich in 1865 along a narrow 1067 mm gauge.

South East Queensland became the scene of war against the coalition of Aboriginal tribes from 1843 to 1855.