The Prime Minister laid a wreath at the tomb of the unknown soldier before the Last Post was played.
Arlington, across the Potomac River from Washington D.C., is home to approximately 400,000 graves of fallen US servicemen.
President Trump and vice-President Mike Pence laid wreaths at the cemetery last week at the start of their inauguration events.
Former Ukip leader Nigel Farage also recently laid a wreath at the grave of the sole British soldier to be buried at Arlington.
Theresa May laid a wreath at Arlington Cemetery
The Prime Minister will visit President Trump later
May meets Trump: Historic first meeting in pictures
Fri, January 27, 2017
The two leaders will spend about an hour in face-to-face talks in the Oval Office, where President Trump has restored a bust of Winston Churchill removed by predecessor Barack Obama.
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Prime Minister Theresa May speaks during the 2017
Theresa May will travel to the White House to become the first foreign leader to meet President Trump
Later, Mrs May will travel to the White House to become the first foreign leader to meet President Trump since his inauguration.
The pair are likely to discuss the prospect of a US-UK trade deal once Britain leaves the EU.
They will hold a joint press conference after their lunch together.
Mrs May will have the opportunity to view the bust of Winston Churchill now that it has been returned to the Oval Office by President Trump.
Last night, the Prime Minister hailed the "unique and special relationship" between Britain and the US in a speech to a Republican Party conference in Philadelphia.
More to follow…