Starmer visits Trump's golf course in Scottish Turnberry, where the two leaders are expected to, among other things, discuss the humanitarian crisis in war-torn Gaza.
"He will discuss further with him what more can be done to secure a ceasefire as soon as possible, put an end to the unspeakable suffering and starvation in Gaza and free the hostages who have been held so cruelly for so long", it says in a statement from Starmer's office.
To "secure peace" in Ukraine is also high on the agenda, according to Downing Street, as well as the implementation of the trade agreement between the USA and the United Kingdom that the two leaders signed in June.
After the meeting at the golf course, they travel together to Aberdeen for a private meeting.