All victims are Pakistani citizens and the incident happened in the Swabi area, close to a junction for the motorway which connects the northwestern city of Peshawar to the capital Islamabad and the eastern city of Lahore.
Swabi district police chief Abdul Rashid Khan confirmed seven deaths.
"They were on their way back home when unknown gunmen on a motorcycle opened fire on their vehicle," he told AFP.
"Six women and a man have died. The driver is injured. We are investigating the motives of the attack," he added.
At least five of the women were teachers.
Police said the victims worked for a local charity that works on health and education, and that they were attached to a community centre in a Swabi village.