Otava has also been at the forefront of encyclopedia-publishing in Finland, with many well-known series, such as the Otavan Suuri Ensyklopedia (Otava's Big Encyclopedia).
Otava a fost, de asemenea, principala editură de enciclopedii din Finlanda, cu mai multe serii binecunoscute, cum ar fi Otavan Suuri Ensyklopedia (Marea Enciclopedie Otava).