Outgoing President Mohamed Ould Ghazouani, 67, is expected to be the clear favorite in the election, though he has not yet announced his candidacy.
Ghazouani has been at the helm of the vast West African country since 2019 and provided stability in the Sahel region, which faces rising jihadism.
He has prioritized the fight against poverty after the Covid-19 pandemic and war in Ukraine caused a sluggish economy.
Last year his party, El Insaf, won a landslide victory in legislative elections -- taking 107 of the 176 seats in the National Assembly, well ahead of the Islamist party Tewassoul, which won 11 seats.
Seven prominent opponents have so far said they will take part in the election.
The well-known anti-slavery activist and opponent Biram Dah Abeid, who was a runner-up in the last presidential election, has also said he intends to stand as a candidate.
Under the terms of the decree, the electoral campaign will begin at midnight on June 14 and end at midnight on June 27.
The decree specifies that voting will begin at 07:00 am and end at 07:00 pm.