It's not known whether the nineteen-year-old was killed in battle or by extremists after trying to return to his Melbourne home.
The family of 19-year-old Irfaan Hussein has confirmed his death but did not comment on how he had died, the Herald Sun reports.
It is believed however, that he was either killed in a bomb blast or was beheaded as he attempted to flee the Middle East.
The Dandenong North teen, who called himself Abu Sufyan Al Australi, attended school with Numan Haider, who was shot dead last year after stabbing two Melbourne police officers.
Police told a court earlier this month that another Melbourne teenage terror suspect, Harun Causevic, had Hussein's international phone number when he was arrested for allegedly plotting attacks on Anzac Day.
Premier Daniel Andrews was careful not to comment on the teen's death before being briefed later on Monday.
"These are really significant issues of international security and again we'll get some briefings today," he told reporters.
Hussein is the fourth Victorian to be killed while fighting for IS in the Middle East in the past three months.
