The Chief Executive of RBS, Ross McEwan, has resigned after five and a half years in office.
Mr. McEwan said he had "implemented the strategy" that he had adopted in 2013.
Under his leadership, the bank, which is 62% state-owned, closed hundreds of stores, but made a profit of £ 1.62bn last year, more than double the previous year's profit.
He remains in the role until a successor has been appointed.
"It's never been easy to stay somewhere like RBS, but with the restructuring largely completed and the bank set up on a sound and profitable footing, I've implemented the strategy I set for 2013. Now I feel like the Right time aside for me and for a new CEO who runs the bank, "McEwan said in a statement.
When Mr. McEwan took over in 2013, RBS made losses and had operations in 30 countries.
His strategy was to reduce the size of the bank by withdrawing from overseas markets. Last year, the bank was active in 12 countries.
In UK banking, which includes Natwest, he has cut costs by closing branches.
In 2014, the bank employed 109,000 people, compared with 67,100 at the end of last year.
After nine years of losses, RBS returned to profitability in 2017 and once again paid dividend payments last year.