Electric bikes, or e-bikes, are close substitutes for cars and two-wheelers because they cover longer distances with less effort. Thus, e-bikes will play a key role in shifting passenger and freight trips away from high-polluting private vehicles and generating fewer emissions if used at scale. While vehicle electrification has focused primarily on large, high-polluting vehicles like buses, trucks, and cars, electrification of bicycles has been largely overlooked as a critical and promising climate and mobility strategy. As a result, many countries and cities have not yet clearly defined what e-bikes are, what quality standards they must meet, and where they can be used safely and efficiently. This report, developed with support from the Climateworks Foundation, aims to define ‘e-bikes’ and evaluate how and where they are being used, the benefits and challenges to widespread adoption, and the ways in which governments can respond to their growing popularity.