He will be in the UK from today until Wednesday, December 4.
The Queen will be greeting Nato leaders as part of events marking 70 years of the alliance.
Nato (the North Atlantic Treaty Organisation) will then meet at The Grove in Watford, on December 4.
President Trump will have separate talks with German Chancellor Angela Merkel, French President Emmanuel Macron and Nato Secretary General Jens Stoltenberg and attend a working lunch with representatives from Estonia, Greece, Latvia, Poland, Romania, Lithuania, Bulgaria, and the United Kingdom.
What is Nato?
The North Atlantic Treaty Organisation was formed in 1949 after the end of the Second World War.
The aim of Nato is to make sure that its 29 member countries don’t fight each other; instead they use their forces to work together for world peace.
Nato has been used increasingly in situations where the world has decided urgent military action is needed.
Will there be protests?
Thousands are expected to attend the demonstration to highlight potential risks to the NHS in a future US-UK trade deal.
How have UK politicians reacted to the visit?
The two leaders won’t be having a one-on-one meeting, according to the White House.
“We have very close relationships and friendships with the United States at every level of government, but what we don’t do traditionally as loving allies and friends is get involved in each other’s election campaigns.”
We pay for your stories! Do you have a story for The Sun Online news team? Email us at firstname.lastname@example.org or call 0207 782 4368 . You can WhatsApp us on 07810 791 502. We pay for videos too. Click here to upload yours.