The Office is divided into three sections: the General Legal Section; the Non-Proliferation and Policy-Making Section; and the Nuclear and Treaty Law Section. The Office provides legal advice to the Director General, the Secretariat and Policy-Making Organs of the IAEA, and, on request, to Member States.

Responsibilities include support and providing advice to meetings of the IAEA General Conference and Board of Governors; depositary functions for treaties concluded under IAEA auspices on behalf of the Director General; assistance to Member States and the IAEA in the negotiation and conclusion of international agreements; and support to Member States in the implementation of IAEA legal instruments and the development of national nuclear laws. The Office also represents the IAEA in litigation procedures, particularly before the Administrative Tribunal of the International Labour Organization.