The Mexican Wolf (Canis lupus baileyi) is a subspecies of the Gray Wolf. It is native to North America, where it is the rarest and most genetically distinct subspecies.

The Mexican Wolf is the smallest Gray Wolf subspecies present in North America. Reaching an overall length no greater than 1.2–1.5 metres (3.9–4.9 ft) and a maximum height of about 80 centimetres (31 in), it is around the size of a German Shepherd. Weight ranges from 27–37 kilograms (60–82 lb). In stature, it resembles some European wolves, though its head is usually broader, its neck thicker, its ears longer and its tail shorter.

The Mexican Wolf was described by both naturalists Hernández and Fernandez.

Until recent times, the Mexican Wolf ranged the Sonoran and Chihuahuan Deserts from central Mexico to western Texas, southern New Mexico, and central Arizona. By the turn of the 20th century, reduction of natural prey like deer and elk caused many wolves to begin attacking domestic livestock, which led to intensive efforts by government agencies and individuals to eradicate the Mexican Wolf. Hunters also hunted down the wolf because it killed deer. Trappers and private trappers have also helped in the eradication of the Mexican Wolf. (Note that recent studies completed by genetics experts show evidence of Mexican Wolves ranging as far north as Colorado). These efforts were very successful, and by the 1950s, the Mexican Wolf had been eliminated from the wild. In 1976, the Mexican Wolf was declared an endangered subspecies and has remained so ever since. Today, an estimated 340 Mexican Wolves survive in 49 facilities at the United States and Mexico.