Thousands of students across three Adelaide schools were forced into hiding today — crouching under desks and sheltering in cupboards — after reports of an armed man on campus.

But the terrifying lockdown was sparked by a misunderstanding with the “gun” being a wooden prop for a school play.

WATCH ABOVE: Fake wooden gun sparks multi-school lockdown.

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Just after midday, Gleeson College students were ordered to take cover before being moved into a gymnasium.

Neighbouring Pedare Christian College and Golden Grove High were also locked down as police swarmed the shared campus.

“We didn’t really know what to think… we’ve only ever done practice drills, so it felt real,” student Lachlan Smith told 7NEWS.

A wooden gun made for a school play has sparked three schools to be lockdown Credit: Supplied/7NEWS

Students say officers tackled the suspected gunman to the ground — only to discover he was a drama teacher carrying a handcrafted prop made in the school’s woodworking room for a World War II‑themed production.

“That’s where the misunderstanding has come from,” student Ryan Jackson said.

Police quickly determined no offence had been committed, but students told 7NEWS staff made the right call by treating the report seriously.

“I think they handled it well, and the cops did their thing,” student Blake Amos said.