John Cregan may refer to:
John Cregan (born 21 May 1961) is a former Irish Fianna Fáil politician. He served as a Teachta Dála (TD) and Senator from 1998 to 2011. He is from Dromcolliher, County Limerick.
On 23 June 1998, Cregan was elected to the 21st Seanad Éireann on the Labour Panel, at a by-election to fill the seat vacated by the Labour Party senator Seán Ryan, who had been elected to Dáil Éireann at a by-election.
Cregan was first elected to Dáil Éireann at the 2002 general election for the Limerick West constituency and was re-elected at the 2007 general election.
On 1 February 2011 Cregan announced that he would not be a candidate at the imminent general election following disagreement with the new leader of Fianna Fáil, Micheál Martin.
John Francis Cregan (January 29, 1878 – December 26, 1965) was an early twentieth century American athlete who specialised in the 800 metres. He participated in Athletics at the 1900 Summer Olympics in Paris and won the Silver medal in the Men's 800 metres event.