Think Big was an interventionist state economic strategy of the Third National Government of New Zealand, promoted by the Prime Minister Robert Muldoon (1975–1984) and his National government in the early 1980s. The Think Big schemes saw the government borrow heavily overseas, running up a large external deficit, and using the funds for large-scale industrial projects. Petrochemical and energy related projects figured prominently, designed to utilise New Zealand's abundant natural gas to produce ammonia, urea fertiliser, methanol and petrol.

The Third National Government of New Zealand was the government of New Zealand from 1975 to 1984. It was an economically conservative government that aimed to preserve the Keynesian economic system established by the First Labour government and was also socially conservative. Throughout its three terms it was led by Robert Muldoon, a populist but antagonistic politician who was sometimes described as the National Party's best asset and worst liability.