美国国家光学天文台（National Optical Astronomy Observatory，缩写为NOAO）成立于1982年，目的是巩固和集成大学天文研究协会（AURA）下属的地面光学天文台，总部位于美国亚利桑那州的图森。由基特峰国立天文台（KPNO）、托洛洛山美洲际天文台（CTIO）、美国国家太阳天文台（NSO）和国家光学天文台双子科学中心（NGSC）等4个天文学研究机构组成，大学天文研究协会负责管理和运作，由美国国家科学基金会资助。

The National Optical Astronomy Observatory (NOAO) is the United States national observatory for ground based nighttime ultraviolet-optical-infrared (OUVIR) astronomy. The National Science Foundation (NSF) funds NOAO to provide forefront astronomical research facilities for US astronomers. However, professional astronomers from any country in the world may apply to use the telescopes operated by NOAO under the NSF's "open skies" policy. Astronomers submit proposals for peer review to gain access to the telescopes which are scheduled every night of the year for observations (with the exception of Christmas and New Year's Eve). The combination of truly open access and the merit based science proposal process makes NOAO unique in the world.