The finance chief of Norwegian since the low-fares carrier was established in 2002 is standing down.
The airline confirmed that Frode Foss has decided to leave the company.
Investor relations vice president Tore Østby, who joined the airline in 2014, is to take on the role of chief financial officer on an interim basis.
Norwegian chief executive, Bjørn Kjos, said: “I am very grateful for the work Frode Foss has done for Norwegian throughout all these years.
“He has done a great job for Norwegian since the company was established, and it is understandable that he, after 15 years as CFO, wants to concentrate on other tasks.”
Foss added: “It’s been a fantastic journey and I’m pleased that Bjørn Kjos let me take part in building the company to what it is today.
“Now it’s time for me to explore new ventures. I wish Norwegian all the best for the future.”