The Dublin Lockout of 1913 was the most severe industrial dispute in the history of Ireland, a general lockout of workers in Dublin, meant to contain the expansion of trade unions.

The chairman of the Dublin United Tramway Company , industrialist and newspaper proprietor William Martin Murphy , was determined not to allow the Irish Transport and General Workers' Union (ITGWU), led by James Larkin, to unionise his workforce. On 15 August he dismissed forty workers he suspected of ITGWU membership, followed by another 300 over the next week. On 26 August the tramway workers officially went on strike. Led by Murphy, over four hundred of the city's employers retaliated by requiring their workers to sign a pledge not to be a member of the ITGWU and not to engage in sympathetic strikes.

The resulting industrial dispute was the most severe in Ireland's history. Employers in Dublin engaged in a lockout of their workers, employing blackleg labour from Britain and elsewhere in Ireland. Dublin's workers, amongst the poorest in the then United Kingdom, were forced to survive on generous but inadequate donations from the British Trades Union Congress (TUC) and other sources in Ireland, doled out dutifully by the ITGWU.

For seven months the lockout affected tens of thousands of Dublin's workers and employers, with Larkin portrayed as the villain by Murphy's three main newspapers, the Irish Independent, the Sunday Independent and the Evening Herald. Other leaders in the ITGWU at the time were James Connolly and William O'Brien, while influential figures such as Pádraig Pearse, Countess Markievicz and William Butler Yeats supported the workers in the generally anti-Larkin media.

The lockout eventually concluded in early 1914 when the calls for a sympathetic strike in Britain from Larkin and Connolly were rejected by the British TUC. Although the actions of the ITGWU and the smaller UBLU were unsuccessful in achieving substantially better pay and conditions for the workers, they marked a watershed in Irish labour history. The principle of union action and workers' solidarity had been firmly established. Perhaps even more importantly, Larkin's rhetoric, condemning poverty and injustice and calling for the oppressed to stand up for themselves, made a lasting impression.