Trump's 18-year-old son withdraws from political debut
Barron, who has been largely shielded from the public eye, made global headlines this week when it appeared he would be the latest member of the Trump family to enter the political arena.
But a statement from the office of his mother, Melania Trump, the former president's third wife, soon put a stop to the convention plan.
"While Barron is honored to have been chosen as a delegate by the Florida Republican Party, he regretfully declines to participate due to prior commitments," it said.
The convention in Milwaukee, Wisconsin, will see Trump's official crowning as the Republican challenger to Democratic President Joe Biden, with delegates from each state designating their candidate for the November election.
Barron would have appeared alongside his siblings Donald Trump Jr., Eric Trump and Tiffany Trump as part of the Florida delegation.
Barron lived in the White House as a child when his father was president but has been fiercely protected from public view.
Trump's eldest daughter, Ivanka, was a senior adviser in his presidency alongside her husband, Jared Kushner, while Don Jr. and Eric are regulars at Trump rallies and on the campaign trail.
In March, the Republican National Committee elected Eric's wife, Lara, to a leadership position.