RTÉ Director General Noel Curran has announced his decision to stand down from the role in May 2016.
Mr Curran was appointed Director General in 2011 and over the course of five years in the role he oversaw a programme of significant restructuring across RTÉ.
Speaking about his departure, Mr Curran said: "After five years as Director General and 12 years on the RTÉ Executive Board, I feel the time is right to move on and take on new professional challenges.
"Through the considerable efforts of staff, management and independent producers the organisation is on a more stable footing.
"Most importantly, through all their combined talents, RTÉ continues to produce strong programming, continues to innovate, and has made the transition to a modern digital media organisation."
Mr Curran said: "There is still a lot of work to be done before my departure in May."
He added: "In particular, I am very much looking forward to preparing for and leading RTÉ's coverage of both the upcoming General Election and the 2016 Commemorations - two hugely important national events.
"Finally I want to thank everyone I've worked with during my time as Director General, both inside and outside RTÉ."
Minister for Communications Alex White paid tribute to Mr Curran and said: "Noel has provided strong leadership and direction to RTÉ throughout a period of major change in Irish broadcasting, against a backdrop of significant financial pressures on the station in a fast-moving and highly competitive market.
"His clear vision for public service broadcasting in the digital era has helped steer RTÉ through the highly successful switch to Saorview and the development of the broadcaster's online platform.
"He has been a part of the RTÉ family for over 20 years. Noel is a man of outstanding character, and a highly accomplished television producer, who has been a huge asset to the organisation. I want to thank him warmly for the excellent service he has given to RTÉ, and to the people of Ireland, over the last 20 years, and I wish him well in his future endeavours."
Mr White said the RTÉ Board would begin the process of finding a replacement shortly.
Chair of the RTÉ Board Moya Doherty said: "The Board collectively, and I as chair, owe Noel a great debt, and his experience and insight will be truly missed.
"I know, however, that these skills will stand him well in the next phase of his career and we wish him well for his future ventures."
