The Finnish Society of Sciences and Letters (Swedish: Finska Vetenskaps-Societeten r.f., Finnish: Suomen Tiedeseura r.y., Latin: Societas Scientiarum Fennica) is a Finnish academy for natural sciences, social sciences and humanities. It is a bilingual (Swedish and Finnish) science academy and the oldest of the four science academies in Finland.
The society was founded in 1838 and is based in Helsinki. It has a total of 120 full ordinary Finnish members, excluding members who have reached the age of 67 (a member who reaches the age of 67 retains the rights as a member but leaves his or her chair open for election of a new member), and about 120 foreign members. It is divided into four sections: I: mathematics and physics, II: biosciences, III: humanities, and IV: social sciences.
The society publishes a yearbook, Sphinx, and the book series Commentationes Humanarum Litterarum, Commentationes Scientiarum Socialium, Bidrag till kännedom av Finlands natur och folk and The History of Learning and Science in Finland 1828-1918. It also awards a number of prizes and grants for scientific and scholarly work.
In addition to the Finnish Society of Sciences and Letters, there are three other academies in Finland: the Finnish Academy of Science and Letters and two academies of engineering sciences. The four Finnish academies have an umbrella organisation for cooperation, the Council of Finnish Academies.