According to Sábado magazine, the boy, known as Abu al-Faruq, was aged 15 and is believed to have moved to Syria last summer.
Portuguese authorities have so far been unable to confirm the news of the boy’s death which is thought to have occurred during an aerial bombing raid by allied forces.
This news comes after social media networking sites last week reported that the boy’s father, Abu Juwairiya al-Portughali had been killed in combat in Syria.
Details first emerged of the incident when a Kuwaiti journalist revealed the information on Twitter. According to reports, the Portuguese Jihadist, was feared by his colleagues and had a high rank within the terrorist organisation.
Lisbon estimates that between 12 and 15 Portuguese nationals have enlisted to fight for the Islamic State.