The leader of the National Party of Australia (formerly the Australian Country Party and National Country Party) is elected by majority vote of the federal parliamentary party. A deputy leader is elected in the same fashion. The party's longest-serving leader is Earle Page, who held the office from 1921 to 1939. The party's current leader is David Littleproud, who has held this office since 2022. It is historically rare for the incumbent leader and deputy leader to be opposed in a bid for re-election.

In every instance when an incumbent leader retires he is always succeeded by his deputy. With the exception of the election of Ian Sinclair in 1984, every one of these deputy leaders ascended to the leadership unopposed.

• 1920: A vote for the leadership and deputy leadership was held on 25 February 1920, prior to the opening of parliament the following day. William McWilliams was elected party leader and Edmund Jowett was elected deputy leader. Both elections were unopposed, with eleven members voting.^[1]
• 1921: A vote for the leadership and deputy leadership was held on 5 April 1921. Earle Page replaced William McWilliams as leader. Edmund Jowett did not re-contest the deputy leadership and was replaced by Henry Gregory.^[2]
• 1922: A vote for the deputy leadership was held on 27 June 1922. William Fleming was elected deputy leader in place of Henry Gregory, who had resigned in February 1922 over policy differences.^[3][4]
• 1923: A vote for the leadership and deputy leadership was held on 16 January 1923, following the 1922 federal election. Earle Page was re-elected unopposed as leader. William Gibson was elected unopposed as deputy leader, following William Fleming's defeat at the election.^[5]
• 1926: A vote for the leadership and deputy leadership was held on 12 January 1926, following the 1925 federal election. Earle Page was re-elected unopposed as leader and William Gibson was re-elected unopposed as deputy leader.^[6]
• 1929: A vote for the leadership and deputy leadership was held on 19 November 1929, following the 1929 federal election. Earle Page was re-elected unopposed as leader. Thomas Paterson was elected as deputy leader, following William Gibson's defeat at the election.^[7]

• 1932: A vote for the leadership and deputy leadership was held on 17 February 1932, following the 1931 federal election. Earle Page was re-elected as leader and Thomas Paterson was re-elected as deputy leader.^[8]
• 1932: A vote for the leadership was held on 12 October 1932. Earle Page resigned the leadership to seek a vote of confidence, following criticism of his handling of negotiations to form a coalition with the United Australia Party. There was no opponent to his re-election, however Senator Charles Hardy dissented from the motion.^[9]
• 1934: A vote for the leadership and deputy leadership was held on 22 October 1934, following the 1934 federal election. Earle Page was re-elected unopposed as leader and Thomas Paterson was re-elected as deputy leader.^[10]
• 1937: A vote for the leadership and deputy leadership was held on 27 November 1937, following the 1937 federal election. Earle Page was re-elected unopposed as leader. Harold Thorby was elected as deputy leader following Thomas Paterson's retirement. The vote for the deputy leadership was controversial. An initial ballot was held using preferential voting, with Thorby, John McEwen, Archie Cameron, and Horace Nock as candidates. McEwen defeated Thorby by one vote following the elimination of Cameron and Nock, but there was confusion as to whether preferences had been distributed correctly. As a result, a second ballot was held in which Thorby defeated McEwen by one vote. It was reported that Larry Anthony, a newly elected MP, had abstained from voting in the first ballot due to his unfamiliarity with the candidates, but was prevailed upon to vote for Thorby in the second.^[11]
• 1939: A vote for the leadership was held on 13 September 1939, following Earle Page's resignation. Archie Cameron was elected leader, defeating John McEwen by seven votes to five. Before the vote, four breakaway members of the party – Oliver Badman, Thomas Collins, Bernard Corser, and Arthur Fadden – were excluded from the meeting. Earlier in the year they had left the parliamentary party in protest at Page's leadership. It was reported that the four MPs were all supporters of McEwen, and the outcome of the leadership vote would have been reversed if they had been allowed to vote.^[12]

• 1950: A vote for the leadership and deputy leadership was held on 21 February 1950, following the 1949 federal election. Arthur Fadden was re-elected unopposed as leader and John McEwen was re-elected unopposed as deputy leader.^[13]
• 1951: A vote for the leadership and deputy leadership was held on 11 June 1951, following the 1951 federal election. Arthur Fadden was re-elected unopposed as leader and John McEwen was re-elected unopposed as deputy leader.^[14]
• 1954: A vote for the leadership and deputy leadership was held on 7 July 1954, following the 1954 federal election. Arthur Fadden was re-elected unopposed as leader and John McEwen was re-elected unopposed as deputy leader.^[15]
• 1956: A vote for the leadership and deputy leadership was held on 6 January 1956, following the 1955 federal election. Arthur Fadden was re-elected unopposed as leader and John McEwen was re-elected unopposed as deputy leader.^[16]

• 1958: A vote for the leadership and deputy leadership was held on 26 March 1958, following Arthur Fadden's retirement. John McEwen was elected unopposed as leader. Charles Davidson was elected unopposed as deputy leader in place of McEwen.^[17]
• 1958: A vote for the leadership and deputy leadership was held in December 1958, following the 1958 federal election. John McEwen was re-elected as leader and Charles Davidson was re-elected as deputy leader.^[18]

• 1961: A vote for the leadership and deputy leadership was held on 19 December 1961, following the 1961 federal election. John McEwen was re-elected unopposed as leader and Charles Davidson was re-elected unopposed as deputy leader. The votes were held at a joint meeting of the coalition parties, which also saw Robert Menzies and Harold Holt re-elected unopposed to the equivalent positions in the Liberal Party.^[19]
• 1963: A vote for the leadership and deputy leadership was held on 11 December 1963, following the 1963 federal election. John McEwen was re-elected unopposed as leader. Charles Adermann defeated Hugh Roberton and Senator Harrie Wade for the deputy leadership, following the retirement of Charles Davidson.^[20]
• 1966: A vote for the leadership and deputy leadership was held on 8 December 1966, following the 1966 federal election. John McEwen was re-elected unopposed as leader. Doug Anthony defeated Ian Sinclair for the deputy leadership, following the retirement of Charles Adermann.^[21]
• 1969: A vote for the leadership and deputy leadership was held on 10 November 1969, following the 1969 federal election. John McEwen was re-elected unopposed as leader and Doug Anthony was re-elected unopposed as deputy leader.^[22]

• 1971: A vote for the leadership and deputy leadership was held on 2 February 1971, following John McEwen's retirement. Doug Anthony was elected unopposed as leader. Ian Sinclair was elected deputy leader in place of Anthony, defeating Peter Nixon by a close margin; the result was "not generally expected".^[23]
• 1972: A vote for the leadership and deputy leadership was held on 13 December 1972, following the 1972 federal election. Doug Anthony was re-elected unopposed as leader and Ian Sinclair was re-elected unopposed as deputy leader.^[24]
• 1974: A vote for the leadership and deputy leadership was held on 4 June 1974, following the 1974 election. Doug Anthony was re-elected as leader and Ian Sinclair was re-elected as deputy leader.^[25]