Donnchadh Ó Briain (17 November 1897 – 22 September 1981) was an Irish Fianna Fáil politician and Conradh na Gaeilge activist.
He was educated at Ahalin national school and then at the Redemptorist College at Mount St Alphonsus, Limerick city, but was prevented from going to university by bouts of ill health.
By 1917, he had become involved in the independence movement as a member of Sinn Féin and later, of the West Limerick brigade of the Irish Republican Army.
He was deeply involved in the Conradh na Gaeilge, which he also joined in 1917, having been influenced by Fr Tomás de Bhál.
In 1920 Ó Briain was appointed Conradh na Gaeilge organiser for County Limerick, and from 1925 he served in that role for all of Munster province, founding numerous branches of the league.