This book constitutes the refereed proceedings of the ACM/IFIP/USENIX 14th International Middleware Conference, held in Beijing, China, in December 2013. The 24 revised full papers presented were carefully reviewed and selected from 189 submissions. The papers cover a wide range of topics including design, implementation, deployment and evaluation of middleware for next-generation platforms such as cloud computing, social networks and large-scale storage and distributed systems. The middleware solutions introduced provide features such as availability, efficiency, scalability, fault-tolerance, trustworthy operation and support security and privacy needs.