Armed police were deployed after reports of a masked man with a firearm in Droitwich, only to discover it was a child with a toy gun.
West Mercia Police moved to reassure residents in the Addyes Way area following a 999 call at 18:00 BST on Thursday.
It said armed officers quickly apprehended an individual who turned out to be a 12-year-old boy dressed up.
He was taken home, the force said, and the family were given advice.
Responding on Facebook, many residents thanked police for their response and said the child seemed tall for his age.