| Office: | Senator |
| Term Start: | 21 April 1948 |
| Term End: | 31 May 1950 |
| Constituency: | Labour Panel |
| Office1: | Senator |
| Term Start1: | 11 December 1922 |
| Term End1: | 29 May 1936 |
| Birth Place: | County Roscommon, Ireland |
| Nationality: | Irish |
| Alma Mater: | College of Commerce, Rathmines |
John Thomas O'Farrell (1887 – 2 January 1971) was an Irish Labour Party politician and trade union official.[1] He was born in Churchborough, County Roscommon in 1887, and was educated at the College of Commerce, Rathmines. He was a member of the Railway Clerks' Association and served as the president of the Irish Trades Union Congress in 1927.[2]
He was an unsuccessful Labour Party candidate for the Dublin North-West constituency at the 1922 general election.[3] He was elected to the new Irish Free State Seanad in 1922 for 3 years.[1] He was re-elected for a 12-year term at the 1925 Seanad election and served until the Free State Seanad was abolished in 1936.[1] He also stood unsuccessfully for the Dublin County constituency at the 1943 general election.[3] He was elected to the 6th Seanad Éireann in 1948 by the Labour Panel. He resigned from the Seanad on 31 May 1950.[4]