The woman, identified as Reza Gul, picked up arms after her son, who was leading a small group of police forces in a village in Farah, was killed by Taliban militants.
Five Taliban militants have also been injured in the gun battle, which lasted for almost seven hours.
The mother of the slain police officer was supported by her daughter and daughter-in-law in her battle against the militants.
The Taliban terrorist group has not made any comments about the incident so far.
Afghan Interior Ministry spokesman Sediq Siddiqui said the woman’s armed battle was a symbol of a major revolution and public uprising against the Taliban militants.
Farah is one of the most insecure provinces in western Afghanistan where armed militants frequently carry out insurgency operations against the government.
Taliban militants have recently stepped up their attacks against Afghan government troops, foreign forces and civilians.
They have vowed to escalate the assaults on Afghan forces and US-led troops, their bases, diplomatic missions and vehicle convoys before the drawdown of US-led foreign forces by the end of the year.
The United States and its allies invaded Afghanistan in 2001 as part of Washington’s so-called war on terror. The military offensive removed the Taliban from power, but insecurity continues across the country despite the presence of tens of thousands of US-led troops.