Trump will meet Ryan and his leadership team at Republican National Committee headquarters on Capitol Hill. He will later meet Senate Majority Leader Mitch McConnell and his top associates. The Trump campaign said the agenda for the gatherings will include "issues of mutual interest".
Tensions within the party over Trump have only worsened in the week since he effectively clinched the nomination following the departures of rivals Ted Cruz and John Kasich. Former GOP nominee Mitt Romney, members of the Bush family and other top Republicans have declined to endorse Trump publicly. Romney, who ran in 2012 with Ryan as his running mate, blasted Trump on for suggesting he would not release his tax returns until after the election.
The real estate mogul will need party resources behind his White House run if he hopes to run a competitive bid against likely Democratic rival Hillary Clinton.
The Trump campaign is finalising plans with the RNC to set up a joint fundraising committee - a "victory fund" - to solicit donations far larger in magnitude than what the campaign itself is legally allowed to accept. The additional funds are routed to the party's war chest then used to finance national get-out-the-vote operations.
A group of senior party financiers is expected to direct the fund, according to people familiar with the plans.
Romney raised nearly US$500 million in 2012 through such an agreement with three national GOP committees and four state parties. That effort began in April 2012 and yielded US$140 million in contributions by the end of June 2012.
Ahead of their meeting, Ryan struck a conciliatory tone, telling reporters he was eager to develop a relationship with Trump.
"We just need to get to know each other. And we as a leadership team are enjoying that we have a chance to meet with him," Ryan said. "This is a big-tent party. There's plenty of room for different policy disputes in this party. We come from different wings of the party. The goal here is to unify the various wings of the party around common principles so that we can go forward unified."
Should the two remain at odds, "I think the consequences would be pretty severe, frankly," said Congressman Kevin Cramer, one of a handful of early Trump endorsers in the House. "I think they'd be more severe for the institution of the House than it would be for Donald Trump."
Ryan faces a tough balancing act, seeking to hold fast to his own brand of ideological conservatism while mending divides in the House GOP ahead of the general election.