Nuttall's oak is a medium to large-sized tree with a rounded, open crown of spreading branches.
Leaves are alternate, simple, 3–6 inches long, widest above the middle; usually with 7 narrow, long-pointed lobes with 1–5 bristle-tipped teeth; notches between lobes rounded and wide. Upper surface dull green, smooth; lower surface paler with tufts of hairs in the vein axils; leaf stalk rather slender, smooth, ¾–2 inches long.
Bark is gray-brown, smooth; becoming blackish, shallow-grooved and with flat, scaly ridges with age.
Twigs are slender, smooth, green to reddish-brown, turning gray with age.
Flowers April–May, in catkins.
Fruits September–October; acorns solitary or paired, dark brown, usually striped the length of the nut, 1 inch long, oblong; cup covering one-third to five-eighths of the nut, thin, hairy, sloping or stalked at the base, scales small and flattened. Acorns ripen in autumn of the second year.