Mabo v Queensland (No 2) (commonly known as the Mabo case or simply Mabo; /mɑːboʊ/ MAH-bo) is a landmark decision of the High Court of Australia that recognised the existence of Native Title in Australia. It was brought by Eddie Mabo and others against the State of Queensland, and decided on 3 June 1992. The case is notable for being the first in Australia to recognise pre-colonial land interests of Indigenous Australians within the common law of Australia.

Mabo is of great legal, historical, and political importance to Aboriginal and Torres Strait Islander Australians. The decision rejected the notion that Australia was terra nullius (i.e. owned by no one) at the time of British settlement, and recognised that Indigenous rights to land existed by virtue of traditional customs and laws and these rights had not been wholly lost upon colonisation.

The Prime Minister Paul Keating during his Redfern speech praised the decision, saying it "establishes a fundamental truth, and lays the basis for justice". Conversely, the decision was criticised by the government of Western Australia and various mining and pastoralist groups.

Soon after the decision, the Keating government passed the Native Title Act 1993 (Cth), which supplemented the rights recognised in Mabo and set out a new process for applicants to have their rights recognised through the newly established Native Title Tribunal and the Federal Court of Australia.

The case centred on the Murray Islands Group, consisting of Murray Island (known traditionally as Mer Island), Waua Islet and Daua Island. The islands have been inhabited by the Meriam people (a group of Torres Strait Islanders) for between 300 and 2,000 years.

Prior to and after annexation by the British, rights to land on Mer is governed by Malo's Law, "a set of religiously sanctioned laws which Merriam people feel bound to observe". Under this law, the entirety of Mer is owned by different Meriam land owners and there is no concept of public ownership. Land is owned by the eldest son on behalf of a particular lineage or family so that land is jointly owned individually and communally. Unlike western law, title to land is orally based, although there is also a written tradition introduced to comply with State and Commonwealth inheritance and welfare laws. However, ownership is not 'one way' under this system of law, and an individual both owns the land and is owned by it. As such, they have the responsibility to care for and share it with their clan or family and maintain it for future generations.

In 1871, missionaries from the London Missionary Society arrived on the Torres Strait island of Darnley Island in an event known as "The coming of the Light" leading to the conversion to Christianity of much of the Torres Strait, including Mer Island. This however did not lead to a replacement of traditional native traditions, but a synthesis with traditional customs, including Malo's Law, being recognised within the framework of Christianity. Reverend David Passi, who gave evidence in the trial, explained that he believed that God had sent Malo to Mer Island and that "Jesus Christ was where Malo was pointing."

In 1879, the islands were formally annexed by the State of Queensland.