The Leader of the Opposition is a title held by the leader of the second-largest party in the New South Wales Legislative Assembly, the lower house of the Parliament of New South Wales. There is also a Leader of the Opposition in the Legislative Council. The leader acts as the public face of the opposition, leading the opposition on the floor of parliament. They act as a chief critic of the government and ultimately attempt to portray the opposition as a feasible alternate government. They are also given certain additional rights under parliamentary standing orders, such as extended time limits for speeches.

The Parliament of New South Wales, formally the Legislature of New South Wales, is the bicameral legislative body of the Australian state of New South Wales (NSW). It consists of the monarch, the New South Wales Legislative Assembly and the New South Wales Legislative Council. Each house is directly elected by the people of New South Wales at elections held approximately every four years. The legislative authority of the parliament derives from section 5 of the Constitution Act 1902 (NSW). The power to make laws that apply to New South Wales is shared with the Federal Parliament. The houses of the New South Wales Parliament follow the Westminster parliamentary traditions of dress, Green–Red chamber colours and protocols. The houses of the legislature are located in Parliament House on Macquarie Street, Sydney.