RAWTHORPE High School has been hit by arsonists, who caused thousands of pounds damage.
And in another incident, an arsonist started a blaze in a classroom at Longley School.
The vandals struck last night about 7pm at Rawthorpe.
They broke into the school and poured petrol along corridors.
They then set fire to the fuel, causing extensive damage to glass doors, partitions and light fittings.
Around £10,000 of damage is thought to have been caused.
Firefighter Brian Rhodes said it was fortunate nothing flammable was in the corridor.
He said: "There was nothing substantial to burn but there was a lot of smoke damage. It caused some disruption to the school."
Police arrived at the scene within minutes and apprehended one youth on the school playing fields and another nearby.
A 16-year-old from Bradley Mills Lane and a 14-year-old from Birstall are being questioned at Huddersfield Police Station in connection with the incident.
Pc Dave McSweeney, of Huddersfield police, said the situation could have been more dangerous.
Vandals also sparked a blaze that severely damaged a classroom at Longley School.
Fire crews were called to the school - which caters for children with special needs - on Saturday evening.
A window was broken and an arsonist set fire to papers that were on top of a filing cabinet in a classroom.
The fire was contained to the room, but the heat had started to melt fixtures and fittings, including the lights.
Two fire crews from Huddersfield station were on the scene within 10 minutes and quickly had the blaze under control.
Mr Mohammed Riaz, the school's deputy head, said three classrooms were out of action today due to smoke and water damage.
"We hope that two out of the three classrooms will be back in use tomorrow.
"Children are being accommodated elsewhere in the school. It could have been worse."