| William Duffy | |
| Office: | Teachta Dála |
| Term Start: | June 1927 |
| Term End: | September 1927 |
| Constituency: | Galway |
| Office2: | Member of Parliament |
| Term Start2: | October 1900 |
| Term End2: | December 1918 |
| Constituency2: | South Galway |
| Birth Date: | 7 April 1865 |
| Birth Place: | County Galway, Ireland |
| Death Place: | County Galway, Ireland |
| Nationality: | Irish |
| Party: | National League Party |
| Otherparty: | Irish Parliamentary Party |
William John Duffy (7 April 1865 – 1 January 1945) was an Irish nationalist politician from County Galway.[1] He was one of the few people to have served both in the United Kingdom House of Commons and in Dáil Éireann.
His parents were Laurence Duffy from Lisduff, County Galway (1827–1872) and Mary Higgins of Athenry, County Galway (1827–1899).
Duffy was elected at the 1900 general election as Member of Parliament (MP) for South Galway,[2] as an Irish Parliamentary Party candidate, and held the seat until his defeat at the 1918 general election by the Sinn Féin candidate Frank Fahy.[3]
At the June 1927 Irish general election, he was elected as National League Party Teachta Dála (TD) for Galway.[4] He did not contest the September 1927 Irish general election.[5]