The unilateral cease-fire will begin Monday as the Muslim holiday of Eid al-Adha gets under way, according to Ahmed Deniz, a spokesman for the Kurdistan Workers' Party, or PKK, which has bases in northern Iraq.
He said the group's military and political leadership would like to resolve its conflict with Turkey peacefully.
"The military and political leadership of the PKK announces a nine-day, unilateral cease-fire ... which is considered a first step toward peace," Deniz told The Associated Press.
Turkey has ignored a series of PKK cease-fire declarations in the past, vowing to fight until all militants are killed or surrender.
The rebels are fighting for autonomy in the predominantly Kurdish-inhabited southeast Turkey. The fight has claimed the lives of tens of thousands of people since 1984.
This year, Turkey has launched several air strikes, including one on Friday, and one major ground operation against rebel bases across Iraq's border.
Eid al-Adha, an important Muslim holiday, lasts four days, but Deniz said the cease-fire would continue for nine days.