What does he want to achieve?
Firstly, Donald Trump hopes that his symbolic choice of the home of Islam’s holiest sites as his first stop can persuade the Islamic world he is not anti-Muslim.
After an election campaign in which he was accused of stoking Islamophobia, and where he pledged to ban Muslims entering America, his aides say he wants to reset his image.
He also needs to reinvigorate alliances with Middle Eastern powers that had been neglected by Barack Obama. Ties with Saudi Arabia are in particularly bad shape, with the kingdom feeling Mr Obama was too eager to appease its main regional rival, Iran, while negotiating a deal to rein in Tehran’s nuclear programme.
Shared opposition to the Iran deal, which Mr Trump has called “disastrous”, will form the bedrock of a new friendship with Saudi Arabia.
Being able to strengthen ties with Saudi Arabia and other Muslim nations is critical to Mr Trump’s ambition of eradicating the Islamic state group and fighting radicalisation.
Announcing his trip, he said he wanted to “begin to construct a new foundation of cooperation and support with our Muslim allies to combat extremism, terrorism and violence, and to embrace a more just and hopeful future for young Muslims in their countries”.
But he is not going to jeopardise the chance of that help by lecturing them from podiums, he has suggested.
He said: “Our task is not to dictate to others how to live, but to build a coalition of friends and partners who share the goal of fighting terrorism and bringing safety, opportunity and stability to the Middle East.”
What challenges will he face?
Unease at Mr Trump’s failed attempt to ban citizens from seven Muslim-majority countries could still linger.
The new US leader will also have to persuade those he meets that for all his America First campaign trail rhetoric, he can still be a genuine ally in international affairs.