The Tanganyika groundnut scheme, or East Africa groundnut scheme, was a failed attempt by the British government to cultivate tracts of its African trust territory Tanganyika (now part of Tanzania) with peanuts. Launched in the aftermath of World War II by the Labour Party administration of prime minister Clement Attlee, the goal was to produce urgently needed oilseeds on a projected 3 million acres (5,000 sq miles, or over 12,000 km²; an area almost as big as Yorkshire) of land, in order to increase margarine supplies in Britain and develop a neglected backwater of the British Empire. Despite an enormous effort and at a cost of £36 million (equivalent to over £1 billion in 2020 value), the project was a disastrous failure and was finally abandoned as unworkable in 1951.

The scheme's proponents, including Minister of Food John Strachey, had overlooked warnings that the environment and rainfall were unsuitable, communications were inadequate, and the whole project was being pursued with excessive haste. The management, initially by the United Africa Company as Managing Agent and subsequently by the government-run Overseas Food Corporation, was appalling, and the scheme came to be popularly seen as a symbol of government incompetence and failure in late colonial Africa. The scheme was described in 1953 as "the worst fiasco in recent British colonial history."