In a statement, Saudi Foreign Minister Adel al-Jubeir said Thursday's summit coincides with a humanitarian cease-fire in the conflict in Yemen, where a Saudi-led coalition is fighting Shiite rebels known as Houthis.
He said Crown Prince Mohammed bin Nayef, who is also interior minister, would lead the Saudi delegation and the king's son, Deputy Crown Prince Mohammed bin Salman, who is defense minister, will also attend.
President Barack Obama had planned to meet Saudi King Salman one-on-one a day before the gathering of leaders at the presidential retreat but the White House did not take his decision to skip the summit as a sign of any substantial disagreement with the US.
The tiny island kingdom of Bahrain said separately that its delegation would be headed by the country's crown prince, Salman bin Hamad Al Khalifa.
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Bahrain, whose leadership has close ties to the Saudis, is an important military ally of the US.
It is the longstanding host to the Navy's 5th Fleet, which is responsible for operations around the Arabian Peninsula and northern Indian Ocean, and is Washington's main naval counterbalance to Iran.
At the summit, leaders of Gulf nations will be looking for assurance that Obama has their support when the region feels under siege from Islamic extremists and Syria, Iraq and Yemen are in various states of chaos.