She was on her way to work when the gunmen on motorcycle fired at her, killing her on the spot, in Jamrud sub-district of Khyber tribal agency, PTI reported.
She was killed instantly, the officials of the local political administration said.
Sawaira is based in Hayatabad area of Peshawar, the capital of Khyber-Pakhtunkhwa province, and works for the rights of women.
No group claimed responsibility for the attack.
The Taliban and Islamic clerics have threatened NGOs in several parts of northwest Pakistan and the tribal belt bordering Afghanistan.