The Kačupys is a river of Kėdainiai district municipality, Kaunas County, central Lithuania. It is the right tributary of the Dotnuvėlė river. It starts from the Krakės-Dotnuva forest, then goes through Siponiai and meets the Dotnuvėlė nearby Vainotiškiai village.

The name Kačupys means 'Cat River' (i. e. is could mean 'petty, inferior river').