Quercus stellata (Post oak) is an oak in the white oak group. It is a small tree, typically 30 to 45 feet tall and 15 to 30 inch trunk diameter, though occasional specimens reach 90 feet tall and 60 inch diameter. It is native to the eastern United States, from Connecticut in the northeast, west to southern Iowa, southwest to central Texas, and southeast to northern Florida. It is one of the most common oaks in the southern part of the eastern prairies.

 The leaves have a very distinctive shape, with three perpendicular terminal lobes, shaped much like a Maltese Cross. They are leathery, and tomentose (densely short-hairy) beneath. The branching pattern of this tree often gives it a rugged appearance. The acorns are 1.5–2 cm long, and are mature in their first summer.

The name refers to the use of the wood of this tree for fence posts. Its wood, like that of the other white oaks, is hard, tough and rot-resistant. This tree tends to be smaller than most other members of the group, with lower, more diffuse branching, largely reflecting its tendency to grow in the open on poor sites, so its wood is of relatively low value as sawn lumber. It is also a popular wood for smoking Texas barbecue.