Femme Simon Gaastra (born 23 July 1945 in Leeuwarden, Netherlands) was a Dutch Professor of maritime history at the University of Leiden and a leading expert on the history of the Dutch East India Company.
Gaastra attended the Rijks Lyceum in Heerenveen and began his studies in history at the University of Leiden in 1965, receiving his doctorate in March 1972.
In 1972–73, he began working as a researcher with the Nederlandse Organisatie voor Zuiver Wetenschappelijk Onderzoek on Dutch-Asiatic Shipping.
In 2004, he succeeded Jaap R. Bruijn, as Professor of Maritime History.
Gaastra retired from this post at the University of Leiden in June 2010 and was succeeded by Hendrik J. den Heijer, a specialist in the history of the Dutch West India Company.