EuroMPI is the preeminent meeting for users, developers and researchers to interact and discuss new developments and applications of message-passing parallel computing, in particular in and related to the Message Passing Interface (MPI). The annual meeting has a long, rich tradition, and the 20th European MPI Users' Group Meeting will again be a lively forum for discussion of everything related to usage and implementation of MPI and other parallel programming interfaces. Traditionally, the meeting has focused on the efficient implementation of aspects of MPI, typically on high-performance computing platforms, benchmarking and tools for MPI, short-comings and extensions of MPI, parallel I/O and fault tolerance, as well as parallel applications using MPI. The meeting is open towards other topics, in particular application experience and alternative interfaces for high-performance heterogeneous, hybrid, distributed memory systems.