自行车锁是一种防范自行车被盗的安保装置，通常的手段是将自行车栓在固定的物体上，如自行车架。

带有快拆杆的车轮和车座（座管紧固件）是防范自行车被盗的固有挑战，因为这令它们可轻易从（除最廉价档次外的大部分自行车的）自行车架上拆除。若未把车轮和车架都锁上，车轮可能被单独卸下。最佳的锁车方法是将两者同时上锁：或是拴在固定物体上，或是将车轮和车架栓在一起。？？

上锁装置有各种尺寸和不同的安全性。安全性越高的种类就越大、越重、越不便携。较小巧的设备可用于防范较生疏、慌乱的盗贼。因此，类似其他安保设备，选择自行车锁时要权衡其安全性、便携性和经济性。有些产品由特别昂贵的材料制成，因为这些材料的强度较高而密度较低。

A bicycle lock is a security device used to deter bicycle theft, generally by fastening the bicycle to a fixed object, e.g., a bike rack.

An inherent challenge to bicycle theft prevention is wheels and bicycle seats (seatpost fastener) with a quick-release lever, making them detachable from the frame (on most but the most economical of bicycles). Unless both wheels and frame are secured, wheels can be removed separately. An optimal locking method will secure the frame as well as both wheels — either to a fixed object or to each other.