Police said they were investigating the motive for the attack. Charity workers have been the target in the past of attacks blamed on Islamist militants and other gunmen.
The victims - all Pakistanis - worked for a Pakistani charity which runs health and education projects, said Abdul Rashid Khan, police chief for Swabi district where the killings took place.
They were on their way home from a local community center when they were attacked.
“Four men came on two motorbikes. They attacked their van, a Toyota HiAce. They opened fire to the right and left of the van and fled on their motorbikes,” Khan said.
“Six women and a man have died. The driver is injured,” he said.
They were shot near a junction for the motorway which connects the northwestern city of Peshawar to the capital Islamabad and the eastern city of Lahore.
Rooh ul-Amin, who heads an umbrella organisation of charities in Swabi, said the victims worked for Ujalla, which was formerly known as the Swabi Women Welfare Society and which ran classes on health education and employed health visitors.
He said his initial information was that five women teachers, one woman health worker and a male health technician were killed.
Police also identified five women teachers among the dead, saying they worked for a local charity that promotes health and education at a community centre in a Swabi village.
Last month, nine polio vaccination workers were shot dead in a string of attacks in Karachi and northwest Pakistan.
The killings prompted the UN children's agency and the World Health Organization to suspend work on polio campaigns in the country.
Also last month a Swedish charity worker was critically injured after a gun attack in the eastern city of Lahore where she worked for the US-founded Full Gospel Assemblies.
The organization runs charities including a technical training institute, adult literacy center and orphanage. Police said the Swedish woman had lived in Pakistan for 38 years.
In August 2011, US development worker Warren Weinstein was kidnapped after gunmen tricked their way into his Lahore home. Pakistani officials believe he is being held by Al-Qaeda and Taliban extremists in Pakistan's lawless northwest.
In April 2012 a British Muslim Red Cross worker was beheaded nearly four months after being kidnapped in the southwestern city of Quetta.