| Malčius | |
| Mouth Coordinates: | 55.2903°N 24.0558°W |
| Subdivision Type1: | Country |
| Subdivision Type2: | Region |
| Length: | 18.3km (11.4miles) |
| Basin Size: | 51.3km2 |
| Tributaries Left: | Drigantas |
The Malčius is a river of Kėdainiai district municipality, Kaunas County, central Lithuania. It flows for and has a basin area of . It starts in the Lančiūnava-Šventybrastis Forest and flows mostly southwards. It meets the Obelis river (from the right side) by Aristavėlė village.
The entire course is channelized. Malčius passes through the villages of Pliupai, Stebuliai, Katkai, Aristava and Aristavėlė. Several ponds (Malčius, Aristavėlė 1st, Aristavėlė 2nd) are on the Malčius river.
The hydronym derives from Lithuanian verbs malšyti, malšinti ('to still, to quieten'), malšti ('to become still, to relent').