The Cornuproetus trilobite is an extinct species of trilobite that lived during the Devonian period. Trilobites are a class of arthropods that first appeared more than 500 million years ago and were among the most successful lifeforms of their time. Cornuproetus is notable for its distinct physical characteristics and its prevalence in certain fossil deposits.

Scientists classify Cornuproetus as part of the Proetida order of trilobites, a group that survived until the end of the Paleozoic era. The name Cornuproetus roughly translates to "horned Proetus," referring to its prominent glabellar (headplate) features that resemble small horns.