The White oak (Quercus alba) is one of the most magnificent of oaks. Normally not a tall tree, typically 30m tall at maturity, it nonetheless becomes quite massive and has been known to live over five hundred years. Some very large specimens can be found, the tallest known being 44m tall. This species lends its name to one of the principal groups of oaks, the white oaks, Quercus subgenus Quercus section Quercus; see the list of Quercus species for the other groups.

Its wood is the best and most valuable of the white oaks, although wood of most of the other white oaks may be marketed with it.

The White oak is fairly tolerant of a variety of habitats, and may be found on ridges, in valleys, and in between, and in dry and moist habitats, and in moderately acid and alkaline soils. The leaves are entire and variously lobed. Sometimes the lobes are shallow, extending less than half-way to the midrib, but sometimes they are deeply lobed, with the lobes somewhat branching. The bark is a light ash-gray and somewhat peeling, variously from the top, bottom and/or sides.

The acorns are long and thin relative to most oaks, and are a valuable wildlife food. Acorns of White oak were used by Native Americans as a food; they are much less bitter than the acorns of red oaks. They also are a favorite food of turkeys, wood ducks, pheasants, grackles, jays, nuthatches, thrushes, woodpeckers, rabbits, squirrels and deer.

The White oak makes an outstanding shade tree, with an exceptionally wide spread and almost never dropping limbs. However, it does not tolerate urban conditions well, although it may thrive in residential neighborhoods.

It is sometimes confused with the Swamp white oak, a closely-related species, and the Bur oak.

The Wye Oak, probably the oldest living White oak until it was felled by a storm in 2002, was the state tree of Maryland.