The Arab nations include Bahrain, Saudi Arabia, Jordan and the UAE, with Qatar playing a supporting role.
The strikes were aimed at the IS’s stronghold of Raqqa in eastern Syria.
“Fighter and bomber jets and Tomahawk missiles were used in the attack,” Pentagon spokesman Rear Adm John Kirby said, bbc.com reported.
The strikes were expected as part of President Barack Obama’s pledge to degrade and destroy IS, who have taken control of large swathes of territory in Iraq and Syria.
The US has already launched 190 airstrikes in Iraq since August.
Rear Adm Kirby confirmed the strikes, saying US military and partner nation forces were undertaking military action in Syria, but he refused to give details.
“Given that these operations are ongoing, we are not in a position to provide additional details at this time,” he said in a statement.