For other uses, see William O'Brien (disambiguation).

William O'Brien (2 October 1852-25 February 1928) was an Irish journalist, writer and politician, particularly associated with campaigns for land reform in Ireland during the late 19th and early 20th centuries.

O'Brien was born at Bank Place in Mallow, County Cork, and moved to Cork City as a young man where he worked on the Daily Herald and Freeman's Journal newspapers.

In 1878, he met Charles Stewart Parnell at a Home Rule meeting and subsequently became editor of the Irish Land League's journal, United Irishman. His association with Parnell and the Irish Parliamentary Party led to him being arrested and imprisoned with him in October 1881, when he helped draft the No Rent Manifesto.

In 1883, he was elected as MP for Mallow and later for Cork and North Cork, but amid the turmoil of Irish politics in the late 19th century was frequently arrested and imprisoned for his support for various Land League protests.

In 1887 O'Brien helped organise a rent strike at the estate of Lady Kingston near Mitchelstown. On 9 September, after an 8,000-strong demonstration led by John Dillon, three estate tenants were shot dead, and others wounded, by police at the town's courthouse where O'Brien had been brought for trial on charges of incitement. This event became known as the Mitchelstown Massacre.

Even in prison, O'Brien continued his protests (refusing to wear prison uniform in 1887, for example); ironically, his imprisonment also inspired protests – notably the 1887 'Bloody Sunday' riots in London. In 1889, he escaped from a courtroom but was sentenced in absentia, eventually serving four months in Clonmel and Galway gaols.

While in prison in 1889, O'Brien wrote a novel, a Fenian romance with a land reform theme set in 1860: When We Were Boys (published in 1890 and acclaimed by Bram Stoker, among others).

He then travelled to America and in 1891 became disillusioned with Parnell's political direction. In 1898, he helped found the United Irish League, trying to bring nationalists and unionists together. As MP for Cork City (elected in 1902), O'Brien campaigned strongly for the Wyndham Land Purchase Act of 1903, which effectively ended landlordism.

He left the IPP for five years during the 1900s, and in 1910 helped found the All-Ireland League. He remained resolutely opposed to partition, however, voting against the 1914 Home Rule Bill, and – against popular opinion from 1916 onwards - opposing the establishment of the Irish Free State. In this political climate, he felt unable to continue as a MP and he did not contest the general elections in 1918, contenting himself with writing.

His works include

• Irish Ideas (1893)
• A Queen of Men, Grace O'Malley (1898)
• An Olive Branch in Ireland (1910)
• The Downfall of Parliamentarianism (1918)
• Evening Memories (1920)
• The Irish Revolution (1921)
• Edmund Burke as an Irishman (1924)