Mammal-like reptiles is a term used to describe the prehistoric animals that appear to be the reptilian ancestors of mammals. The term is most commonly used to describe the group Therapsida (although it can be also used as a more broad term to describe any of the Synapsids that are non-mammalian). The Cynodonts were the most mammal-like of the Therapsids.

The term is not considered a formal one by most experts, for, technically speaking, the mammal-like reptiles are closer on the evolutionary branch to mammals than to the traditionally defined reptiles (thus, 'reptile-like mammals' would be a more accurate term).