Flannery, Thomas J. (Ó Flannghaile, Tomás) (1846–1916), Irish-language scholar and revivalist, was born 5 April 1846 in Ballinrobe, Co. Mayo, second son of Pádraig Ó Flannghaile and his wife Sadhbh Ní Chlochartaigh. He began his education under Peadar Ó hOisín, a local schoolmaster. In 1853 the Flannery family emigrated to Manchester, where he attended St Wilfrid's school. One of his teachers there, a Mr Corrigan, fostered an interest in his native language and taught him basic literacy in Irish. Flannery spent a number of years as a pupil teacher at St Wilfrid's before entering the catholic training college in Hammersmith, west London (1865). He went on to teach English and Latin for many years in various schools and training colleges in London and Manchester, and also served for a time as examiner in Celtic to the Intermediate Education Board. He retired in 1907.
His work for the Irish language included classes and occasional lectures in the Southwark Irish Literary Club (founded 1883) and its successor, the Irish Literary Society (founded 1892). As chairman of a sub-committee which was set up by the latter in 1896, he played a major role in the founding in 1898 of the Irish Texts Society. In November 1897 he was elected first president of the Forest Gate branch of the Gaelic League. His publications include editions with metrical translations of Micheál Coimín (qv), Laoi Oisín ar thír na n-óg (1896) and Donnchadh Ruadh Mac Conmara (qv), Eachtra ghiolla an amaráin (1897). In 1896 he published a collection of essays, For the tongue of the Gael, a copy of which Patrick Pearse (qv) received as a school prize. He later corresponded with Pearse when the latter was editor of An Claidheamh Soluis. Other publications by Flannery include De prosodia Hibernica (1908) and Duanaire na macaomh (1910). A selection of his translations of Latin and English poetry are published in Donnchadh Ó Liatháin's Tomás Ó Flannghaile, scoláire agus file (1940). This book also contains a selection of his original verse in Irish, including the well-known hymns ‘Gabham molta Bhríde’ and ‘Dóchas linn Naomh Pádraig’.
Flannery and his wife Maria (maiden name and date of marriage unknown) had two daughters and four sons. His eldest daughter, Máire, served as president of the London branch of the Gaelic League (1935–42). He died 4 November 1916 at home at 38 St George's Road, Forest Gate, London.