The emergence of open access is one of the most significant changes to the world of scholarly publications since the migration from print to digital publishing began. Reports of some authors have demonstrated how libraries across the membership are changing, in response to a need for new services and an increasingly diverse client group. In order to contribute to the existing knowledge in the area of open access movement in libraries, this chapter discusses how the 21st century library provides a service that can open access to knowledge for the growth and development of communities they serve by highlighting the concept of open access and open content, roles of libraries in open access initiative as well as library collection development and open access. This chapter also sheds light on legal and ethical issues in open access and the future of open access in libraries.