The American Airlines Center, the event's venue, has a capacity of about 20,000.
The arena also plays host to the Dallas Mavericks, a basketball team owned by Mark Cuban, who has spoken in support of Trump.
Cuban said he had no doubt Trump would “kill it” at the Dallas rally, saying “there is nothing more Texan than being confident and entrepreneurial.”
The tech billionaire has also said he would consider being Trump’s vice president if asked.
Trump had to move a Mobile, Ala., campaign event to a bigger venue last month, drawing a crowd estimated at 30,000 people.