Hamza Bin Laden is said to be emerging as a leader of the Islamist militant group. His whereabouts are not known.
In recent years, he has released audio and video messages calling on followers to attack the US and its Western allies in revenge for his father's killing.
US special forces killed Osama Bin Laden in Pakistan in 2011.
He approved the attacks on the US on 11 September 2011, in which nearly 3,000 people were killed.
Hamza Bin Laden, who is believed to be about 30 years old, was officially designated by the US as a global terrorist two years ago.
He married the daughter of Mohammed Atta, who hijacked one of the four commercial aircraft used in the 2001 attacks, and crashed it into one of the World Trade Center towers in New York.
Letters from Osama Bin Laden seized from his compound in Abbottabad where he was killed indicated that he had been grooming Hamza, thought to be his favourite son, to replace him as leader of al-Qaeda, the US state department said.
His whereabouts have been a matter of dispute. He is believed to have spent years along with his mother in Iran, where it is thought his wedding took place.
Other reports suggest he may have lived in Pakistan, Afghanistan or Syria.