The victims, all women, were targeted as they returned home on foot from their school in Khar, the main town of Bajaur district, officials said.
"Five to six militants who were hiding their faces ambushed them. One female teacher died on the spot," Adalat Khan, an administrative official told AFP, adding that her two wounded colleagues had been taken to hospital.
Two intelligence officials also confirmed the incident.
Bajaur was once a stronghold of the Taliban who are opposed to the education of girls and have destroyed hundreds of schools in recent years.
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