Stephen Lake will forgo his role as chief executive and managing director in 2016, once the handover to a new chief executive has been completed.
GBST chairman John Puttick said Mr Lake has served with distinction since assuming the role in 2001.
"Stephen has made an enormous contribution both through his strategy which has enabled GBST to become an international company, and securing some of the world's top banking institutions and financial services companies as long-term clients.
"He now believes that the time is right to transition to a new senior executive to lead the company's further global expansion, and we wish him well for the future,” Mr Puttick said.
Mr Puttick indicated that the company has begun an international search for a new chief executive.
"We intend to appoint a senior executive with the experience to take advantage of global opportunities for the company, leveraging our industry-leading software platforms and strong balance sheet,” he said.
Commenting on his departure, Mr Lake said: “I look forward to handing over to someone who will lead the company on its next phase of global growth.
“I will always be passionate about GBST and am confident the company will continue to prosper in the years ahead.”
