Ismail Ajjawi, a Palestinian student denied entry to the United States last month at the airport in Boston, was allowed to enter the country on Monday and was at Harvard in time for the beginning of classes, according to Amideast, the group that sponsored him.

Amideast said in a statement that the United States Embassy in Beirut reviewed Mr. Ajjawi’s case and reissued a visa. Harvard officials confirmed that Mr. Ajjawi was on campus.

Mr. Ajjawi, 17, landed at Logan International Airport in Boston on Aug. 23 and was turned back after immigration officials objected to his friends’ social media posts, he told The Harvard Crimson, the student newspaper. Mr. Ajjawi, who lives in Tyre, Lebanon, had received a visa before traveling.

The episode prompted a furor among free speech advocates. It became a rallying cry for university officials who are worried that the Trump administration is making it more arduous for foreign students and scholars to study in the United States, and possibly alienating those who would otherwise be inclined to form a favorable impression of American society.