Henry Daglish (18 November 1866 – 16 August 1920) was an Australian politician who was the sixth premier of Western Australia and the first from the Labor Party, serving from 10 August 1904 to 25 August 1905. Daglish was born in Ballarat, Victoria, and studied at the University of Melbourne. In 1882, he worked as a mechanical engineer but soon switched to working in the Victorian public service. He first stood for election in 1896 but failed to win the Victorian Legislative Assembly seat of Melbourne South. He then moved to Subiaco, Western Australia, where he found work as a chief clerk in the Western Australian Police Department. In 1900, Daglish was elected to the Subiaco Municipal Council and in April the following year, he was elected to the Western Australian Legislative Assembly as the member for the newly created seat of Subiaco, becoming one of six Labor members in the Western Australian Legislative Assembly. The party elected him as its whip, and he resigned from the Subiaco council on 1 May 1901. On 1 December 1902, Daglish was sworn in as mayor of Subiaco, having been elected the previous month.

In the 1904 state election, Labor won 22 of the Legislative Assembly's 50 seats, making it the party with the most seats. On 8 July 1904, the Labor Party caucus elected Daglish as the party's leader, and on 9 August, he successfully moved a motion of no confidence in the government of Walter James, who resigned as premier on 10 August. Governor Frederick Bedford then swore in Daglish as premier of Western Australia, colonial treasurer and minister for education. His keynote speech on 23 August was poorly received; militant Labor supporters saw him as giving up on Labor policies. In parliament, Daglish struggled to achieve anything due to a hostile Legislative Council; his one major success was the passing of a new Public Service Act. In June 1905, a cabinet reshuffle decreased Daglish's popularity within the Labor Party but he defeated a motion of no confidence at a caucus meeting later that month. Daglish resigned as premier on 22 August 1905 when his plan to buy the Midland Railway Company for £1.5 million (equivalent to AU$253,000,000 in 2022) failed to pass through parliament. Hector Rason succeeded him as premier on 25 August.

On 27 September 1905, Daglish resigned as leader of the Labor Party. He then left the party and styled himself as an Independent Labor politician. He was again elected Mayor of Subiaco on 5 June 1907 and served until 1908. From August 1907 to September 1910, Daglish held the position of Chairman of Committees, and from September 1910 to October 1911, he was the minister for works in Frank Wilson's Liberal government. At the October 1911 state election, Daglish lost his seat in parliament to Labor candidate Bartholomew James Stubbs and failed to regain the seat at the 1914 state election. Daglish died at his home in Subiaco on 16 August 1920. Daglish railway station and the suburb of Daglish, Western Australia, are named after him.

Henry Daglish was born in Ballarat, Victoria, on 18 November 1866, to Mary Ann (née James) and William Daglish, an engine driver. He was educated in Geelong and in 1881 he attended the University of Melbourne. He gained a mechanical engineering apprenticeship at a foundry in 1882 but a year later, he left engineering to join the public service as a clerk in the Victorian Police Department.

On 20 August 1894, in Carlton, Victoria, Daglish married Edith May Bishop, with whom he had a son, H. Daglish, of the Bank of New South Wales, Narrabeen, and a daughter, Rae Daglish. With an increasing interest in the labour movement, by June 1895, Daglish was the secretary of the United Public Service Association. In September 1895, he went into business as an auctioneer, accountant and legal manager.

In 1895 and 1896, Daglish was a member of the National Anti-Sweating League, a group campaigning against the poor conditions endured by low-paid workers. In 1896, Daglish stood in a by-election for the seat of Melbourne South in the Victorian Legislative Assembly, receiving 34 out of 2,192 total votes. Later the same year, Daglish moved to Western Australia (WA) after taking an offer of £200 (equivalent to AU$35,900 in 2022) to resign from the recession-hit Victorian public service; he settled in the working-class suburb Subiaco, 4 km (2.5 mi) west of Perth, the state capital. Daglish wrote a letter to Premier John Forrest requesting work in the WA public service in 1897; he was offered and accepted a position as assistant to the chief clerk in the WA Police Department. He later resigned and entered business as an auctioneer, accountant and legal manager.

In November 1899, Daglish unsuccessfully stood for election to the Central Ward of the Subiaco Municipal Council. The following year, he was elected unopposed to the council's South Ward, his term starting on 1 December 1900.

Daglish resigned from the public service in 1901 to stand as a Labor Party candidate in the newly created seat of Subiaco in the Western Australian Legislative Assembly. In the 1901 Western Australian state election on 24 April, Daglish was elected to that seat with the largest majority in the state, and became the whip of the Labor Party. The party had only seven members, all of whom, aside from Daglish, represented seats in the mining regions of Murchison and the Goldfields. He tendered his resignation from the Subiaco Municipal Council on 1 May 1901.