Kołłątaj is a Polish language surname. It is commonly rendered into English without diacritics as Kollataj. The Russian language version is Kollontay.
The surname may refer to:
- Antoni Kołłątaj (1776–1794), nephew of Hugo
- Benedykt Kołłątaj , Polish-Lithuanian lieutenant
- Hugo Kołłątaj (1750–1812), Polish Roman Catholic priest, social and political activist, political thinker, historian and philosopher
- Kołłątaj's Forge, a group of activists and writers
- Jan Kołłątaj-Srzednicki (1883–1944), Polish brigadier general
- Rafał Kołłątaj (1750–1833), Polish nobleman and brother of Hugo