United Nations Security Council Resolution 166, adopted on October 25, 1961, after examining the application of the Mongolian People's Republic for membership in the United Nations the Council recommended to the General Assembly that the Mongolian People's Republic be admitted.

Resolution 166 was approved by nine votes to none, with one abstention from the United States. The Republic of China did not participate in voting.

• List of United Nations Security Council Resolutions 101 to 200 (1953–1965)
• History of Mongolia

• Text of the Resolution at undocs.org

• Works related to United Nations Security Council Resolution 166 at Wikisource
• Bolor Lkhaajav (1 November 2021). "Mongolia Celebrates 60 Years in the United Nations". The Diplomat.
• "Ю.Цэдэнбал бол НҮБ ба Монголын харилцааг үндэслэгчдийн нэг" (in Mongolian). Sonin. 26 October 2021.