Iran's Interior Ministry said on August 2 that Ebadi's organization has no valid registration permit and that its activities are therefore illegal.
HRW says in a statement the decision is an "attempt to silence" the group and a "huge setback for protecting human rights in Iran."
Ebadi told RFE/RL on August 7 that her group applied for registration when it was set up four years ago, but that the authorities never issued a permit, despite assurances that they would.
Ebadi's center has defended several prominent Iranian activists and dissidents in the past.