The Syrian Observatory for Human Rights, a Britain-based group, said the deaths raised to 148 the number of civilians killed in US-led strikes in Syria since they began in September.
The Observatory said the family was killed in a coalition strike on the village of Daly Hassan, in the northeast of Aleppo province.
Their deaths "bring the number of Syrian civilians killed in coalition air strikes since September 23 to 148, including 48 children and 32 women," the monitor said.
Syria's US-backed opposition National Coalition urged an investigation into the overnight incident, noting that the available information "lends credence to report that it was a US-led coalition air strike."
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The Pentagon has generally denied that US-led coalition strikes have killed any civilians, despite persistent reports of scattered civilian deaths.
But on May 22, the head of the US-led air campaign acknowledged that a November 2014 raid in Aleppo had killed two children -- the first such admission from Washington.
More than 220,000 people have been killed in Syria since the conflict began with anti-government protests before spiralling into a war after a regime crackdown.