(James J.) Séamus Dwyer (15 November 1886 – 20 December 1922) was an Irish politician.
Serving as an intelligence officer for the Dublin Brigade of the Irish Republican Army, and as a Dáil Court judge he was imprisoned by the British in 1921.
He was elected unopposed at the 1921 elections for the Dublin County constituency as a Sinn Féin Teachta Dála (TD) in the 2nd Dáil.
He voted in favour of the Anglo-Irish Treaty.
He stood as a pro-Treaty Sinn Féin candidate at the 1922 general election but was not elected.On 20 December 1922 he was shot dead in his shop at 5 Rathmines Terrace, Dublin.
by anti-Treaty Volunteer Commdt.
Robert 'Bobbie' Bonfield.
"At about 4.50pm Mr O'Dwyer was talking to a customer when a young man enter the shop, addressing O'Dwyer the young man asked ‘Are you Mr O'Dwyer?’.
O'Dwyer replied yes and the young man said I have a note for you.
The young man reached into the pocket of his overcoat a drew a revolver, he fired twice at O'Dwyer at point-blank range.
O'Dwyer died instantly.
The customer and a shop assistant gave chase but were unable to catch the assassin."O'Dwyer was married.
He was a member of the Peace Committee of ten men which sat in May 1922 which brought about the agreement between Collins and de Valera, he was a personal friend of Michael Collins.