The Waterfront Hall and Ulster Hall are seeking a new chief.
Catherine Toolan, the current chief executive of the events space and conference centre, is moving on after nearly four years in the post.
Sligo-born Ms Toolan started the job in August 2016 and covered the Waterfront Hall's relaunch as the ICC Belfast.
Ellvena Graham, chairman of Belfast Waterfront Ulster Hall, said: "We would like to thank Catherine for the energy, drive and commitment she has consistently shown in her role as chief executive.
"Her passion for selling our city to a global audience is instilled in the senior management team she established, who will continue to lead the venues as we seek to recruit a replacement."
She added that Ms Toolan would remain "a great ambassador" for Belfast.