Onchocerca lupi is an emerging, zoonotic filarioid nematode associated with ocular disease in companion animals. We report the first autochthonous case of O. lupi in a dog from Hidalgo County, southern Texas, USA. An 11-year-old, castrated male, Pitbull dog from McAllen, Hidalgo County, southern Texas with no travel history, was diagnosed with a perforating corneal ulceration of the right eye. Enucleation was performed, and tissues submitted for histopathology. Sections of two filarioid nematodes were observed. Parasite identification relied on morphological features seen on histopathology and molecular confirmation by PCR of the cox1 gene of the mitochondrial DNA, followed by sequencing and phylogenetic analysis. Our finding suggests Texas as an additional endemic state for this zoonotic nematode. Further investigations are required to understand the epidemiology of this parasite along the United States/Mexico border.