In recent years, bike-sharing has experienced rapid development; however, controversies about the externalities of bike-sharing programs have arisen as well. While bike-sharing programs have impacts on traffic, the environment, and public health, the social impacts, the management, and sustainable development of bike-sharing has also been of interest. The debate regards whether there are externalities, as well as whether and how such externalities can be determined. Based on the rapidly diffused bike-sharing in China, this paper quantitatively explores bike-sharing externalities. Specifically, this paper estimates the impacts of bike-sharing on the economy, energy use, the environment, and public health. The empirical results show that bike-sharing programs have significant positive externalities. The bike-sharing systems can provide urban residents with a convenient and time-saving travel mode. We find that the bike-sharing dramatically decreases traffic, reduces energy consumption, decreasing harmful gas emissions, improves public health generally, and promotes economic growth. This study contributes to a better comprehension of the externalities of bike-sharing and provides empirical evidence of the impacts of bike-sharing. Findings suggest that bike-sharing can play a critical role in the process of urban transportation development and provide information useful for urban transportation policies.