梯形烷（英文：ladderane），又称梯烷，是一种含有两个或多个稠合四元环的环烷烃。它的英文名ladderane是一个混成词，因为四元环的排列形状类似于梯子，并且是一种烷烃。有n个环的梯形烷化学式为C_2n+2H_2n+6。梯形烷的空间构型张力很大，因为碳原子上的配体不能使用正常的键角来成键。然而，梯形烷的例子已经在生物体内被发现。 一个典型的例子是五环厌氧氨氧化酸（Pentacycloanammoxic Acid）， 它由五个稠合的环丁烷单元构成。它在细菌中进行厌氧氨氧化过程，这使得它形成了紧且厚的膜，这阻止了生物体失去肼中间体。后者参与了氮的产生和亚硝酸根离子与氨反应生成水。

In chemistry, a ladderane is an organic molecule containing two or more fused cyclobutane rings. The name arises from the resemblance of a series of fused cyclobutane rings to a ladder. Numerous synthetic approaches have been developed for the synthesis of ladderane compounds of various lengths. The mechanisms often involve [2 + 2] photocycloadditions, a useful reaction for creating strained 4-membered rings. Naturally occurring ladderanes have been identified as major components of the anammoxosome membrane of the anammox bacteria, Planctomycetes.