The National Observatory of Athens (NOA; Greek: Εθνικό Αστεροσκοπείο Αθηνών) is a research institute in Athens, Greece. Founded in 1842, it is the oldest research foundation in Greece. The Observatory was the first scientific research institute built after Greece became independent in 1829, and one of the oldest research institutes in Southern Europe. It was built around the same period as the United States Naval Observatory.
The world-renowned Greek-Austrian astronomer Georgios Konstantinos Vouris lobbied to create the National Observatory of Athens in the newly founded state. He persuaded wealthy Greek-Austrian banker Georgios Sinas to pay for the new massive observatory. The Austrian-born Greek King found out the news and awarded Georgios Sinas's son the Order of the Redeemer. The King also selected the architects for the building under Georgios Konstantinos Vouris's supervision, which were Eduard Schaubert and Theophil Hansen.