Mairead McGuinness (born 13 June 1959) is an Irish politician who served as the European Commissioner for Financial Stability, Financial Services and the Capital Markets Union from October 2020 to November 2024. A member of Fine Gael, she previously served as First Vice-President of the European Parliament from 2017 to 2020. She served as a Member of the European Parliament (MEP) for East from 2004 to 2014 and for Midlands–North-West from 2014 to 2020. In the European Parliament, she sat with the European People's Party (EPP). She was selected as Fine Gael's nominee for the 2025 Irish presidential election after being nominated unopposed but she withdrew from the race following medical advice after a hospital stay.

Originally from Ardee in County Louth, McGuinness was the first female graduate of University College Dublin's Bachelor of Science degree in Agricultural economics in 1980. In 1984, she completed a diploma in accounting and finance and followed a career in the media before entering politics in 2004. She worked as a researcher on The Late Late Show, as a presenter on RTÉ's Ear to the Ground and Celebrity Farm, a journalist with the Irish Farmers Journal and editor of the Irish Independent's agricultural supplement.

In 2014, McGuinness was awarded UCD Alumnus of the Year for Agriculture and Food Science.

In early 2004, McGuinness declared her intention to seek a nomination for the European Parliament election for Fine Gael, following speculation linking her to running for the Progressive Democrats. At the selection convention in February 2004, she was selected to run alongside Avril Doyle. This proved controversial, as Fine Gael insiders believed they could win only one of the three seats in the East constituency. However, a stronger than expected performance from Fine Gael in the election saw both women being elected.

During her time in parliament, McGuinness served on several European Parliament committees, including the Committee on Agriculture and Rural Development and the delegation for relations with Australia and New Zealand. She was a substitute member of the Committee on the Environment, Public Health and Food Safety, the Committee on Petitions and the delegation for relations with China.^{[citation needed]}

McGuiness was a Fine Gael candidate for the Louth constituency at the 2007 general election, but was not elected. She was re-elected on the first count at the 2009 European election, topping the poll with 25.7% of the first preference votes.

In April 2011, McGuinness announced that she wished to run for President of Ireland and would seek the Fine Gael party nomination for the 2011 presidential election. During the campaign, McGuinness refused to reveal her MEP expense and allowance claims. In July 2011, she was defeated for the nomination by Gay Mitchell.

At the 2014 European election, she was re-elected to the European Parliament for the new Midlands–North-West constituency.^{[citation needed]}