Purpose - The purpose of this paper is to discuss the concept of flexibility as it applies to libraries. Design/methodology/approach - Specific cases are from the literature introduced where libraries have introduced aspects of flexibility. Lessons that can be learned from other sectors regarding flexibility are also presented. Findings - There are three central themes for libraries to address when considering the various theories and research around flexibility: importance of management, human resources issues and the need to know the user. Flexibility has to be managed proactively as a concept in libraries. Originality/value - The paper provides food for thought for library practitioners in the use of flexibility in an increasingly uncertain world.