United Nations Transparency, Accountability, and Reform Act of 2013

United Nations Transparency, Accountability, and Reform Act of 2013 - Requires the President's annual congressional budget justification to include a detailed itemized request in support of the U.S. contribution to the regular budget of the United Nations (U.N.).

Directs the President to use U.S. influence at the U.N. on a variety of issues, including: (1) shifting the funding mechanism for the regular budget of the U.N. from an assessed to a voluntary basis, (2) terrorism, (3) anti-Semitism, (4) maintaining U.S. influence in the U.N. Security Council, and (5) human rights violators.

Withholds from U.S. contributions to the regular U.N. budget amounts that are proportional to the percentage of such budget expended for a U.N. human rights treaty monitoring body or committee that was established by a convention or an international covenant to which the United States is not party.

Establishes the Office of the United States Inspector General for Contributions to the United Nations System.

Sets forth requirements for the Office with respect to audits and investigations of U.S. contributions to the U.N. and such contributions' use by U.N. entities.

Prohibits the obligation or expenditure of a U.S. contribution to any U.N. entity unless it has provided the Office with a transparency certification and is in compliance with it.

Withholds U.S. contributions from any U.N. entity that recognizes a Palestinian state or grants full membership to the Palestinian observer mission at the U.N., the Palestine Liberation Organization (PLO), the Palestinian Authority (PA), or any other Palestinian administrative organization or governing entity before the achievement of a final peace agreement with Israel.

Declares that until the Secretary makes a specified certification to Congress: (1) the Secretary shall withhold from a U.S. contribution to a regular U.N. budget an amount equal to the amount that would be allocated for the United Nations Human Rights Council (UNHRC), (2) the Secretary shall not make a voluntary contribution to UNHRC, and (3) the United States shall not run for a UNHRC seat.

Withholds from the U.S. contribution to the regular U.N. budget an amount equal to the percentage of such contribution that would be or has been expended by the United Nations pursuant to: (1) the Goldstone Report, and (2) the Durban process.

Prohibits the use of funds for U.S. participation in any further part of the Durban process.

Withholds U.S. contributions to the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) or to any successor or related entity unless the Secretary makes specified certifications to Congress.

Prohibits any U.S. contribution to the International Atomic Energy Agency (IAEA) from being used to support Technical Cooperation program assistance to any country, including North Korea, that: (1) has repeatedly supported acts of international terrorism; or (2) is in breach of, or under investigation for breach of, obligations regarding its safeguards agreement with the IAEA, the Nuclear Non-Proliferation Treaty, or any relevant Security Council resolution.

Sets forth U.S. policy regarding reform of U.N. peacekeeping operations.

Directs the President to use U.S. influence at the U.N. to oppose the creation of new, or expansion of existing, U.N. peacekeeping operations until the Secretary certifies to Congress that specified peacekeeping reforms have been adopted by the U.N. Department of Peacekeeping Operations or the General Assembly.

Sets forth reporting requirements regarding: (1) U.N. reform, (2) U.S. contributions to the United Nations, and (3) U.N. voting practices.