The Wild Boar (Sus scrofa) is the wild ancestor of the domesticated pig. It lives in woodlands in central Europe, the Mediterranean regions, across southern Asia and as far as Indonesia. Animals similar to the wild boar include the warthog of Africa and the peccary or javelina of the American Southwest; but these animals do not share the pig's taxonomic genus.

The wild boar for a long time was extinct in Great Britain, although some are farmed for their meat. In recent decades escaped wild boars have bred into a new wild population in some areas, particularly the Weald. They are capable of causing serious injury and are best avoided.

The term boar can refer to an adult male domestic pig. The difference between the wild and domestic animals is largely a matter of perception; both are usually described as Sus scrofa, and domestic pigs quite readily become feral. The characterisation of populations as wild, feral or domestic and pig or boar is usually decided by where the animals are encountered and what is known of their history.

One characteristic by which domestic breed and wild animals are differentiated is coats. Wild animals almost always have thick, short bristly coats ranging in colour from brown through grey to black. A prominent ridge of hair matching the spine is also common, giving rise to the name razorback in the southern United States. The tail is usually short and straight. Wild animals tend also to have longer legs than domestic breeds and a longer and narrower head and snout. European adult males can be up to 200kg and have both upper and lower tusks; females do not have tusks and are around a third smaller on average.

Wild boars live in groups called sounders. Sounders typically contain around twenty animals, but groups of over fifty have been seen. In a typical sounder there are two or three sows and their offspring; adult males are not part of the sounder outside of the autumnal breeding season and are usually found alone. Birth, called farrowing, usually occurs in the spring; a litter will typically contain five piglets, but up to thirteen has been known.

The animals are usually nocturnal, foraging from dusk until dawn but with resting periods during both night and day. This is because hunters are most active during the day.

Wild boars are hunted rather because they are damaging crops and forrests than for food. One of the Twelve Labors of Hercules was hunting a wild boar. Boar hunting figures in several stories of Celtic and Irish mythology. Such hunting was traditionally done by groups of spearmen.

The wild boar was a symbol of Richard III of England.