John (Johnny) O'Leary (1 September 1894 – 21 June 1959) was an Irish Labour Party politician who served in the Oireachtas for nearly twenty years, first as Teachta Dála (TD) for Wexford and then as a Senator.
He was first elected to Dáil Éireann as a Labour Party Teachta Dála (TD) for the Wexford constituency at the 1943 general election. He was re-elected at the 1944 and 1948 general elections as a National Labour Party TD. At the 1951 and 1954 general elections, he was once again elected as a Labour Party TD.
O'Leary was defeated at the 1957 general election, but was elected to the 9th Seanad by the Administrative Panel.