BBC News NI profiles some of them.
FINE GAEL
Centre-right Fine Gael is the Republic of Ireland's largest political party and is led by Taoiseach (prime minister) Enda Kenny.
Fine Gael came to power in 2011 during Ireland's worst economic crisis in recent memory.
Mr Kenny formed a coalition government with the social-democratic Labour Party and has been campaigning to return to power with the party.
FIANNA FÁIL
Formed by the state's founding father, Éamon de Valera in 1926, Fianna Fail, the centrist party, historically appealed right across all the social divides.
It dominated Irish politics for much of the post-Second World War period.
The party suffered a catastrophic defeat in 2011 after many voters blamed it for the way it handled the economic crisis.
LABOUR
Since 2011, Labour has been in coalition government with Fine Gael.
The Irish Labour Party is a social democratic party, founded in 1912 as part of the trade union movement, with which it maintains organisational links.
For most of the history of the state, it was the third largest party, though it is currently in second position in parliamentary strength.
SINN FÉIN
Although Sinn Féin started building its political base and mandate in Northern Ireland, in recent years the left-wing party has risen to prominence in the Republic of Ireland.
The party has a history going back to 1905, but modern Sinn Féin dates back to 1970.
OTHER PARTIES
There are 13 other political parties contesting seats in the general election. They include the recently formed Renua party and the Anti-Austerity Alliance-People Before Profit.
The four main political parties in the Republic of Ireland are running candidates in Friday's  general election, as are a number of smaller parties.