The Jundul Hafsa, a faction of the Taliban, had claimed responsibility for the June 22 attack at the base camp of Nanga Parbat in Diamer district.
A police official said the arrested men were involved in planning and abetting the crime. "Four of them were directly part of the attack," police official Muhammad Naveed told media.
The victims included one American with dual Chinese citizenship, three Ukrainians, two Chinese, two Slovakians, one Lithuanian and one Nepalese. A Pakistani guide was also killed.
The attack shocked the climbers community as the region was considered safe before the killings.