The Sinn Féin Bank, formally the Sinn Féin Co-operative People's Bank, Ltd. (Irish: Coṁar-Ḃannc Sinn Féin, Teo.) was a co-operative bank in Ireland associated with the Sinn Féin movement, which operated from August 1908 to October 1921. The Sinn Féin Bank is sometimes confused with the National Land Bank, established as a friendly society in 1919 with Dáil backing and premises at 5 Harcourt Street.
The bank was established in 1908 to "carry out the business of banker and Bill Discounter, and of Dealer in , Shares, Bonds, Debentures and other Securities to assist in the development of Irish industries". Its founding council comprised George W. Russell, Arthur Griffith, and P. T. Daly. In 1910 it purchased headquarters at 6 Harcourt Street for £575, leasing the upper floors to the Sinn Féin party, from where the Sinn Féin newspaper was edited. A contemporary wrote, "we do not envy the man who has the job of persuading [nationalists] that the new Sinn Fein bank (which we take it will be established without complying with the requirements of British law) is a secure nest for his savings as the Bank of Ireland".
When the First Dáil proclaimed an Irish Republic in 1919, it opened a "Trustees of Dáil Éireann" account at the Sinn Féin Bank for a "Self Determination Fund" of donations from supporters. The Department of Finance of the Dáil ministry under Michael Collins was also in 6 Harcourt Street in 1919. Kathleen Kearney met her husband Stephen Behan while working at the Sinn Féin Bank. Several times in 1919 and 1920, during the Irish War of Independence, the Dublin Metropolitan Police (DMP) raided and ordered the closure of 6 Harcourt Street. The bank's bookkeeping was deliberately complex, with proxy names for accounts held by republican leaders. In 1923 it was claimed that the authorities "were unable to make head or tail out of" the books it had confiscated.