Willie Walsh will step down from his role as chief executive of International Airlines Group later this year.
He will stand down from the board on March 26th, and will retire on June 30th.
Luis Gallego, currently Iberia chief executive, will succeed Walsh in the role.
Antonio Vázquez, IAG chairman, said: “Willie has led the merger and successful integration of British Airways and Iberia to form IAG.
“Under Willie’s leadership IAG has become one of the leading global airline groups.
“Willie has been the main driver of this unique idea that is IAG.
“I hugely admire his commitment, strong leadership and clear vision, always ready to take on whatever challenges lay ahead of him.
“I am deeply respectful of what he has achieved as chief executive of this group, of his sense of fairness, his transparency and his capacity to integrate people regardless of nationalities or backgrounds.”
“Willie has established a strong management team and I am delighted that Luis will be promoted from this team to succeed Willie as chief executive.”
Walsh joined Aer Lingus as a cadet pilot in 1979, working his way up through the ranks to take the top job it IAG following the merger between British Airways and Iberia in 2011.
During his career, he was also chief executive of British Airways from 2005 until the 2011 merger, as well as chief executive at Aer Lingus from 2001 until 2005.
He held the post of chairman of the IATA board of governors in 2016-17.
Walsh said: “It has been a privilege to have been instrumental in the creation and development of IAG.
“I have had the pleasure of working with many exceptional people over the past 15 years at British Airways and at IAG.
“Luis has been a core member of the team and has shown true leadership over the years and I have no doubt he will be a great chief executive of IAG“.
Luis Gallego’s successor at Iberia will be announced in due course.
Vázquez added: “Luis started his career in the airline industry in 1997 with Air Nostrum and, since 2014, he has been chief executive of Iberia where he has led a profound transformation of this airline.
“The board is confident that Luis is the right person to lead IAG in the next stage of its development and we look forward to working closely with Luis in his new role.”