Many data intensive scientific applications are by nature irregular. They may present irregular data structures, irregular control flow or irregular communication. Current supercomputing systems are organized around components optimized for data locality and regular computation. Developing irregular applications on them demands a substantial effort, and often leads to poor performance. However, executing irregular applications efficiently will be a key requirement for future systems. The solutions needed to address irregular applications challenges can only come by considering the problem from all perspectives: from micro- to system-architectures, from compilers to languages, from libraries to runtimes, from algorithm design to data characteristics. Only collaborative efforts among researchers with different expertise, including end users, domain experts, and computer scientists, could lead to significant breakthroughs. This workshop aims at bringing together scientists with all these different backgrounds to discuss, define and design methods and technologies for efficiently supporting irregular applications on current and future systems.