The Meath East by-election will be held on Wednesday 27 March.
The by-election is being held to fill the seat left vacant by the death of Minister of State Shane MacEntee, who died in December.
Fine Gael's Regina Doherty and Labour's Dominic Hannigan are the two sitting TDs in the constituency.
Taoiseach Enda Kenny moved the writ for the by-election in the Dáil today.
Fianna Fáil candidate Thomas Byrne said he hoped the campaign would be a "positive and constructive debate about the future of our constituency".
Green Party leader Eamon Ryan announced that Seán Ó Buachalla will stand as the party's candidate.
Seamus McDonagh will run for the Workers' Party and Darren O’Rourke will represent Sinn Féin.
The Fine Gael candidate will be selected at a convention on Thursday evening, with speculation that it will be Mr McEntee's daughter, Helen.