The Irish presidential election in 1945 was Éire's first contested presidential election. With the decision of President Douglas Hyde not to seek a second term, Fianna Fáil decided to nominate its deputy leader, Án Tánaiste Sean T. O'Kelly as its candidate. Independent republican Patrick MacCartan sought and failed to receive the necessary four nominations from local councils. Expecting that MacCartan would fail, the main opposition Fine Gael party decided at the last moment to run a candidate. It chose General Sean McEoin. However MacCartan finally managed to get a nomination from twenty members of Oireachtas Éireann, producing an unexpected three candidate race.

In the election, O'Kelly as expected won on the second count. However the degree of voting transfers between the two opposition candidates, and O'Kelly's failure to win on the first count, showed the depth of growing opposition to Eamon de Valera's government and the potential that existed for cooperation among various opposition groups. De Valera's government was defeated in the subsequent 1948 general election and replaced by an Inter-Party government from the opposition. In some ways, the Inter-Party government born in 1948 was conceived due to the results of the 1945 presidential election.