Canadian federal Judge James O'Reilly last month agreed with Khadr's lawyers that the government's refusal to call for his repatriation infringed on their client's rights under the constitution.
Washington claims that Khadr, who left Canada in 1990 with his parents, threw a grenade at a US soldier after a four-hour US bombardment of an al-Qaeda compound in the eastern Afghan city of Khost.
He is the only remaining westerner held at Guantanamo and has charges of murder, conspiracy and support of terrorism against him.
Omar's father, Ahmed Said Khadr, is alleged to have been an al-Qaeda fighter and financier. He was killed during a raid by Pakistani forces in 2003.
Abdullah Khadr, one of Omar’s brothers, is being held in Canada on a US extradition warrant, accused of supplying weapons to al-Qaeda, while another brother has said that the family stayed with Osama bin Laden, the head of al-Qaeda.
But "Omar identifies himself strongly with Canada," Lieutenant-Commander Bill Kuebler, his former US military lawyer, said last year.
Kuebler said that at the time of his arrest by US forces, Khadr was a "frightened, wounded, 15-year-old boy, a boy like other children wrongfully involved in armed conflict who had no business being there, who sat slumped against a bush while a battle raged around him."
Khadr has claimed that he has been treated badly while in detention, first at a military camp in Bagram, Afghanistan, and later at Guantanamo.