Reports on social media suggested pupils of Brooksbank School in Elland were caught up in a disturbance involving youths from outside of the school at around 3.30pm.
The incident is believed to have taken place on the Recreation Ground on Recreation Lane, off Victoria Road.
Several parents have said that their children had been 'terrified' by the brawl, with one saying she was considering keeping her son off school today.
Headteacher Kevin McCallion said: "We always work closely with police to ensure the safety of children in our care. That is always our primary concern.
"Parents can rest assured that Brooksbank is a safe place for their children and that school is open as normal this morning.
"We will keep parents informed on any updates via the school website and through our usual methods of communication."
Mr McCallion is meeting with police later this morning to discuss the incident.