A keyring or "split ring" is a ring that holds keys and other small items, which are sometimes connected to keychains. Other types of keyrings are made of leather, wood and rubber. Keyrings were invented in the 19th century. The most common form of the keyring is a single piece of metal in a 'double loop'. Either end of the loop can be pried open to allow a key to be inserted and slid along the spiral until it becomes wholly engaged onto the ring. Novelty carabiners are also commonly used as keyrings for ease of access and exchange. Often the keyring is adorned with a key fob for self-identification.

Other forms of rings may use a single loop of metal or plastic with a mechanism to open and securely close the loop.