反棱柱（Antiprism）是由两个相同边数多边形平行基底和侧面的三角形所组成的一个多面体。反棱柱的对偶多面体是偏方面体（Trapezohedron）。

在一个边长为a、高为h的n角反棱柱里：
顶点数目：2n
边的数目：4n
面的数目：2n+2
表面积：

In geometry, an n-sided antiprism is a polyhedron composed of two parallel copies of some particular n-sided polygon, connected by an alternating band of triangles. Antiprisms are a subclass of the prismatoids.

Antiprisms are similar to prisms except the bases are twisted relative to each other, and that the side faces are triangles, rather than quadrilaterals.