This Book Constitutes Thoroughly Revised And Selected Papers From The 6th International Conference On Model-driven Engineering And Software Development, Modelsward 2018, Held In Funchal, Madeira, Portugal, In January 2018. The 22 Thoroughly Revised And Extended Papers Presented In This Volume Were Carefully Reviewed And Selected From 101 Submissions. They Contribute To The Development Of Highly Relevant Research Trends In Model-driven Engineering And Software Development Such As Innovative Methods For Mdd-based Development And Testing Of Web-based Applications And User Interfaces, Support For Development Of Domain-specific Languages (dsls), Mdd-based Application Development On Multiprocessor Platforms, Advances In Mdd Tooling, Formal Semantics And Behaviour Modelling, And Mdd-based Product-line Engineering.