The United Nations Security Council veto power is the power of the five permanent members of the UN Security Council to veto any "substantive" resolution. They also happen to be the nuclear-weapon states (NWS) under the terms of the Treaty on the Non-Proliferation of Nuclear Weapons. However, a permanent member's abstention or absence does not prevent a draft resolution from being adopted. This veto power does not apply to "procedural" votes, as determined by the permanent members themselves. A permanent member can also block the selection of a Secretary-General, although a formal veto is unnecessary since the vote is taken behind closed doors.

The permanent members of the United Nations Security Council are the five sovereign states to whom the UN Charter of 1945 grants a permanent seat on the UN Security Council: China, France, Russia, United Kingdom, and United States.