The Liberal Government of New Zealand was the first responsible government in New Zealand politics organised along party lines. The government formed following the founding of the Liberal Party and took office on 24 January 1891, and governed New Zealand for over 21 years until 10 July 1912. To date, it is the longest-serving government in New Zealand's history. The government was also historically notable for enacting significant social and economic changes, such as the Old Age Pensions Act and women's suffrage. One historian described the policies of the government as "a revolution in the relationship between the government and the people".

The New Zealand Liberal Party was the first organised political party in New Zealand. It governed from 1891 until 1912. The Liberal strategy was to create a large class of small land-owning farmers who supported Liberal ideals, by buying large tracts of Māori land and selling it to small farmers on credit. The Liberal Government also established the basis of the later welfare state, with old age pensions, developed a system for settling industrial disputes, which was accepted by both employers and trade unions. In 1893 it extended voting rights to women, making New Zealand the first country in the world to enact universal adult suffrage.