Multilevel language architectures represent a new object-oriented paradigm both for conceptual modelling and software engineering. Different from traditional approaches, they allow for an arbitrary number of classification levels and introduce other concepts that foster reuse and adaptability. While multilevel languages and tools have reached a considerable maturity, the field still offers numerous challenges. The MULTI workshop series is dedicated to bring together experts who develop and apply multilevel language technologies as well as those who focus on specific analysis and design methods or on economic aspects of this new paradigm.