David Campbell will step down as the boss of Wagamama with immediate effect, the company announced today.
Jane Holbrook, the firm's chief operating officer, is set to take his place as chief executive.
In a statement, Wagamama said Campbell will continue to act as special adviser to the company, but it did not give a reason for his departure.
Holbrook, who joined as chief financial officer in 2014, said she was delighted to take on the role at the helm of the company, which is working to build its international presence in Europe and the US.
"[Campbell's] leadership has been inspiring and has helped in establishing Wagamama’s current strong position - probably the strongest and healthiest it has ever been in our long 25 year history.
"Together over the last 12 months David and I have, along with other members of the executive team, devised and set out the business's current growth strategy. It is such an exciting and unique opportunity ahead as we continue growing the business, both domestically and internationally."
Campbell joined the Japanese-inspired restaurant chain as chief executive in 2013.
The company is currently owned by private equity vehicle Duke Street Capital and Hutton Collins. Last month, Edi Truell, a City financier and former Boris Johnson adviser, said he was plotting a bid for the noodle bar chain.
The business is expected to be put on sale soon, according to reports.