| Named By: | J. G. M. Thewissen & S. T. Hussain in 1998 |
| Time Period: | Early Eocene, 50 Ma |
| Location: | Pakistan - Kuldana Formation |
| Size: | Skull estimated to be about 20 centimetres long |
| Diet: | Carnivore |
| Fossil(s): | Partial skull and post cranial skeleton |
| Classification: | | Chordata | Mamamlia | Cetacea | Archaeoceti | Pakicetidae | |
Nalacetus is an extinct pakicetid early whale, fossils of which have been found in Lutetian red beds in Punjab, Pakistan (33.6degN 72.2degE / 33.6; 72.2, paleocoordinates 14.3degN 68.3degE / 14.3; 68.3). Nalacetus lived in a fresh water environment, was amphibious, and carnivorous. It was considered monophyletic by Cooper, Thewissen & Hussain 2009. It was said to be wolf-sized and one of the earliest forms of the order Cetacea.
Nalacetus is known mostly from dental remains from the Lutetian of the Kala Chitta Hill, Punjab, Pakistan:
H-GSP 96055, right palatal fragment with P4 and M1-2.
H-GSP 30306, right maxillary fragment with P2 and partial P3-4; a fragmentary mandible with fragmented teeth together with some isolated lower teeth.
In the cheek teeth of Pakicetus, the protocone lobe increases from the first molar to the third. In Nalacetus, in contrast, the protocone lobe is larger in the first molar than in the second.