WIEM Encyklopedia (full name in Polish: Wielka Interaktywna Encyklopedia Multimedialna - "Great Interactive Multimedia Encyclopedia"; 'wiem' in the Polish language also means "I know") is a Polish Internet encyclopedia.
The first printed edition was released in mid-1990s, with the second in 1998, it contained about 66,000 entries and various multimedia add-ons. It was released online in 2000 by the Polish web portal Onet.pl on the basis of Popularna Encyklopedia Powszechna i Multimedialna ("Popular General and Multimedia Encyclopedia"). From 2004 to 2 March 2006 it was not free, however before and after it was free to access. As of the 9th online edition in 2006, it contains 125,000 entries.