单轮车是只有一个车轮的人力运输工具。由于其故意设计成难以保持平衡的式样所以早期几乎只出现在杂技表演中，而近年则成为一项运动项目。

单轮车由个重要部分组成：轮（包括轮胎、管、轮网、轮辐、轮毂、轮轴）、曲柄、踏板、叉形框架、坐塾直柱、无椅背的坐塾。单轮车和单车用的车轮是一样的，只是单轮车要用特别设计的轮毂，使轮轴能固定在它上。因此曲柄的转动会直接影响车轮的转动（称为 Direct drive 机制）。

A unicycle is a vehicle that touches the ground with only one wheel. The most common variation has a frame with a saddle, and has a pedal-driven direct drive. Unicycling is practiced professionally in circuses, by street performers, and in festivals and as a hobby. Unicycles have also been used to create new sports such as unicycle hockey. In recent years unicycles have been also been used in activities similar to mountain biking or trials.