"I believe that the president is a citizen. I believe the president is a Christian. I'll take him at his word," said Boehner (R-Ohio), appearing on NBC's "Meet the Press."
Boehner spoke after viewing a video of a Republican focus group in Iowa in which a number of people indicated that they thought Obama was a Muslim.
"As speaker of the House, as a leader, do you not think it's your responsibility to speak out against that kind of ignorance?" asked the host, David Gregory.
"It's not my job to tell the American people what to think," Boehner said. "The American people have the right to think what they want to think."
Obama's citizenship and religion came under discussion during the 2008 presidential campaign and have persisted as topics of debate in corners of the conservative blogosphere.
The son of a Kenyan father and an American mother, Obama was born in Hawaii on Aug. 4, 1961. He has said repeatedly that he is a Christian.