"Today he announced that he wants to begin building that wall. Who's going to pay for it?" Greta Van Susteren asked Ryan on MSNBC's "For The Record."
"Well, first off, we're going to pay for it and front the money up," Ryan said.
He said there are "various ways" of getting Mexico to "contribute" to Trump's signature project.
"I know your follow-up question is, is Mexico going to pay for the wall?" Ryan said. "There are a lot of different ways of getting Mexico to contribute to doing this. And there are different ways of defining how exactly they pay for it."
Earlier Wednesday, White House press secretary Sean Spicer also avoided giving specific answers about funding for Trump's wall, saying only that Mexico will pay for the wall "one way or another."