António Manuel de Oliveira Guterres (born 30 April 1949) is a Portuguese politician and diplomat who is serving as the ninth Secretary-General of the United Nations.

The Secretary-General of the United Nations (UNSG or just SG) is the head of the United Nations Secretariat, one of the six principal organs of the United Nations. The Secretary-General serves as the chief administrative officer of the United Nations. The role of the United Nations Secretariat, and of the Secretary-General in particular, is laid out by Chapter XV (Articles 97 to 101) of the United Nations Charter.

The Secretary-General was envisioned by U.S. President Franklin D. Roosevelt as a "world moderator", but the vague definition provided by the UN Charter left much room for interpretation by those who would later occupy the position. According to the UN website, their roles are further defined as "diplomat and advocate, civil servant, and CEO". Nevertheless, this more abstract description has not prevented the office holders from speaking out and playing important roles on global issues to various degrees. Article 97 under Chapter XV of the United Nations Charter states that the Secretary-General shall be the "chief administrative officer" of the Organization, but does not dictate their specific obligations.

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