Seán McGuinness (died 28 October 1978), also known as John McGuinness, was an Irish Republican who was elected to Dáil Éireann but did not take his seat and was later disqualified.
He was elected at the 1923 general election as TD for Laois–Offaly, but never took his seat. He was convicted on 29 October 1925 of assaulting, resisiting and obstructing a sergeant of the Garda Síochána and of a similar charge relating to a Peace Officer. He was sentenced to 18 months imprisonment with hard labour.
He was therefore disqualified from membership of the Dáil on 30 November 1925 under section 51(2)(a) of the Electoral Act 1923.
The resulting by-election for his seat in the 4th Dáil was held on 18 February 1936, and won by the Cumann na nGaedhael candidate, James Dwyer.