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John Stefanos Paraskevopoulos (June 20, 1889 – March 15, 1951) was a Greek/South African astronomer.

He was born in Piraeus, Greece and graduated from the University of Athens. He served in the Greek army during the Balkan Wars and World War I.

In 1919 he went to America for two years, spending part of that time working at Yerkes Observatory where he met and married Dorothy W. Block. In 1921 he returned to Athens where he became head of the Athens Observatory. He left this post due to a lack of funding and went to Arequipa, Peru to work at Boyden Station, a branch of Harvard Observatory, with a view to finding a more suitable location for it.

The decision was made to move Boyden Station to South Africa due to better weather conditions, and Paraskevopoulos served there as director of Boyden Observatory in South Africa from 1927 to 1951.

He co-discovered a couple of comets.