Patricia McKenna (Castleshane, 13 March 1957) is an Irish Green Party politician. She became the first Green Party candidate in Ireland to be elected to European Parliament. She was elected to the European Parliament in 1994 and re-elected in the European elections in June 1999 but lost her seat in the European elections 2004. She acted as one of the Dáil advisers to Ireland's first Green TD, Roger Garland. McKenna has been involved in many campaigns as an MEP and politician. She is perhaps best-known for her victory in the Supreme Court in 1995, in which she argued successfully that it was unconstitutional for the Irish government to spend taxpayers money promoting only one side of the argument in referendum campaigns.

She is also well-known for her opposition to nuclear power, genetically-modified crops, and United States-led military aggression in various parts of the world.

McKenna also campaigned against the Irish government's plan to join NATO's "Partnership for Peace". She is a strong advocate of Irish neutrality and the Shell to Sea campaign and is widely associated with the Eurosceptic wing of her party.

McKenna failed to be elected as Green Party candidate at the 2007 general election in the Dublin Central constituency. She also strongly opposed the 2007 Programme for Government between the Green Party and Fianna Fáil. After the election, she declared herself a candidate for the leadership of the Green Party, but was defeated for the position by current leader John Gormley.