The group said in a statement that the students, who were detained in February, are under physical and psychological pressure. It is not clear what the charges against them are, and they reportedly have very little contact with the outside world.
There has been no reaction from Iranian officials regarding the students' cases.
Four of the students were detained before attending a ceremony marking the anniversary of the death of Mehdi Bazargan, Iran’s first prime minister after the revolution.
The others were detained following a clash between security forces and student activists who were protesting the burial on the Amir Kabir University campus of the remains of Iranian soldiers who died during the Iraq-Iran war. The burial of the unknown soldiers on the campus is seen as a move by Iran’s government to tighten its control over universities.