Sir Joseph Hector McNeil Carruthers KCMG (21 December 1857 – 10 December 1932) was an Australian politician who served as Premier of New South Wales from 1904 to 1907.

Carruthers is perhaps best remembered for founding the Liberal and Reform Association, the forerunner to the modern Liberal Party of Australia (New South Wales Division). Zachary Gorman has argued that Carruthers played a central role in re-orientating Australian liberalism to sit on the centre-right of the political divide, influencing political developments at both the Federal and State level.

Carruthers was born in Kiama, New South Wales to Charlotte née Prince and John Carruthers. He attended William Street National School and Fort Street High School in Sydney. After boarding at George Metcalfe's High School, Goulburn, he went up to the University of Sydney and graduated with a Bachelor of Arts in 1876. He took his Master of Arts degree two years later and was admitted to practice as a solicitor, where he remained for some years. In December 1879, he married Louise Marion Roberts.

In 1887, Carruthers obtained the most votes for the four-member Legislative Assembly seat of Canterbury, on a platform of local issues, free trade, social reform, land reform, industrial conciliation and arbitration, and an elective Legislative Council. He held Canterbury until 1894, when he switched to the new seat of St George. After a successful election largely co-ordinated by Carruthers the Reid ministry was formed in August 1894. Carruthers was given the position of Secretary for Lands, and passed the important Crown Lands Act 1895.

In 1895, he divorced his wife and was granted custody of their children. In 1897, in the Truth, John Norton accused him of irregularities in his divorce, immorality in his private life, and land abuses as Secretary for Lands. Norton was prosecuted for criminal libel but the jury could not agree on a verdict.

When the Federation was established in 1901, Reid went to the Federal House and was replaced as leader by Charles Lee. Lee was not very successful and soon Carruthers replaced him as leader of the New South Wales opposition, creating the Liberal and Reform Association as the successor to the Free Trade Party. The LRA had an innovative structure, with mass membership, coordinated campaign strategies and a permanent executive. Carruthers had deliberately moved the party away from the tariff issue, which was now a Federal responsibility, and established a broad platform embodying the principles of Gladstonian classical liberalism. He positioned his support for enterprise and economic freedom against what he saw as the increasingly socialistic policies of the Progressive Minister for Public Works Edward William O'Sullivan and the Labor Party, arguing that politics required clear 'lines of cleavage' with a two-party system to give people a clear choice at elections. In doing so Carruthers placed his liberal party on the centre-right of the political divide, a move George Reid would copy with his federal anti-socialist campaign.

Carruthers party won the July 1904 election on "an alliance of Liberalism, temperance and Protestantism". The middle Progressive Party was isolated by Carruthers 'lines of cleavage' rhetoric, leaving them with only 16 seats. This new tier of government was set up without a significant increase in taxation, as the existing land tax was transferred to become council rates. In 1907 Carruthers even promised to abolish the income tax, a policy his successor Charles Wade would partially follow through with, abolishing the tax for incomes under £1000. A beginning was also made on the Burrinjuck irrigation dam. In 1907, Carruthers succeeded in forcing a "fusion" of much of the Progressive Party with the LRA, further cementing the liberals as the main opposition to the Labor Party in New South Wales.

Curruthers and the New South Wales Government that he led were strongly opposed to the selection of Dalgety, as the site of Australia's national capital, under the Seat of Government Act 1904. Their opposition to Dalgety and preference for a site in the 'Yass-Canberra' area was important in the later selection of Canberra.