Trump spoke to host President Pedro Pablo Kuczynski earlier this week, after which a US official said his attendance had "not been confirmed."
But the White House now says he will attend, following a call with an old business acquaintance, Argentine president Mauricio Macri.
During today's call, Trump "underscored the need for countries in the region to work together to bring democracy back to the great people of Venezuela," according to the White House.
When Trump travels to Lima, he is likely to encounter protests and perhaps a hesitant welcome from fellow heads of state and government.
Throughout his election campaign and his presidency, Trump has maligned Hispanic migrants and attacked Latin American nations over drugs, trade and the movement of people.
He has promised to build a wall on the US border with Mexico and threatened to tear up a trade deal with Mexico and Canada.
Argentina and Brazil also face the prospect of punitive tariffs on steel exports after Trump's controversial announcement yesterday.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)