Among the dead were four children while 16 others were wounded with some in critical condition, a war monitor says of the attack in the northwestern town, Sarmin.
Land-to-land missiles fired by Syrian regime forces killed eight civilians including four children in a school in northwestern Syria on Wednesday, a war monitor said.
Part of the building in the town of Sarmin had been turned into a shelter for the displaced, the Britain-based Syrian Observatory for Human Rights said.
Sixteen people were wounded with some in critical condition, Observatory head Rami Abdel Rahman said.
An AFP correspondent in Sarmin saw the remains of a missile several metres long fuming in a nearby olive grove.
In the latest round of violence in Syria's nearly nine-year-old war, regime forces have upped their deadly bombardment of the northwestern opposition bastion of Idlib in recent weeks.
In December alone, the violence pushed some 284,000 from their homes in the rebel-run region of some three million people, the United Nations said.
The mass movement of people has seen public buildings such as mosques, garages, wedding halls, and schools turned into shelters, UN humanitarian agency OCHA said.
TRT World's Obaida Hitto has more details on Syria school attack pic.twitter.com/u25p71YQtb— TRT World Now (@TRTWorldNow) January 1, 2020
Ceasefire in tatters
Regime ally Russia announced a ceasefire for Idlib in late August after months of deadly Russian and regime bombardment that killed around 1,000 civilians.
But sporadic clashes and bombardment persisted throughout the autumn before a spike in violence in the past month, the Observatory says.
Syria's civil war has killed more than 400,000 people since it started in 2011 with the brutal repression of anti-regime protests.
In total 11,215 people including more than 1,000 children were killed during the war last year, although it was the least deadly year on record since the beginning of the conflict.