Aer Lingus chief executive Christoph Mueller is step down in May 2015.
The Irish carrier will now start the process of selecting and appointing a successor.
Mueller was appointed five years ago in July 2009 as chief executive.
He said today: “The last five years has involved very hard work for the entire team at Aer Lingus and it is rewarding to see that the company is well positioned both strategically and financially.
“In that context and given it is the fifth anniversary of the date of my appointment, I feel it is the right time to hand over the reins.
“I am conscious that there are significant challenges that we are continuing to address and I am happy to remain with Aer Lingus through May 2015 to apply an ongoing focus to that work.
“I am also happy to facilitate a comprehensive transition to my successor as CEO of Aer Lingus.”
The airline’s chairman Colm Barrington said: ”Under Christoph’s strategic leadership, Aer Lingus has been transformed into a strong, consistently profitable airline with a clear strategic direction, a resilient business model as a value carrier and an improved cost base.
“Christoph has placed Aer Lingus in a position where we can look to the future with confidence and can continue to develop and grow the airline for the benefit of our customers, our employees and our shareholders.”