The customer-owned lender, which faces pressure from regulators to bolster its balance sheet, said that Mr Howe will stand down at its annual meeting in the summer of 2015.
It has started searching for his replacement, and said it will consider its existing non-executive directors as well as external candidates.
The mortgage giant, which has around 15 million members, emerged largely unscathed from the financial crisis, but has encountered mounting pressure over the last few months.
This summer the Prudential Regulation Authority (PRA) ordered Nationwide to draw up plans to plug a hole in its balance sheet by bolstering its leverage ratio.
The Nationwide’s chief executive Graham Beale has criticised the measure as a “crude instrument”.