nextbike is a German company that develops and operates public bike-sharing systems. The company was founded in Leipzig, Germany, in 2004. It operates in cities in 25 countries including Germany, UK, New Zealand, Poland, Croatia, the Czech Republic, Austria, Switzerland, Ukraine, and the United States. The headquarters with about 100 employees are based in Leipzig. The bicycles and stations are maintained by local service partners. Since 2021, nextbike GmbH has been a wholly owned subsidiary of TIER Mobility. As part of the merger, nextbike turned into the joint brand nextbike by TIER.

A bicycle-sharing system, bike share program, public bicycle scheme, or public bike share (PBS) scheme, is a shared transport service where bicycles are available for shared use by individuals at low cost.