This is the refereed proceedings of the 11th International Conference on Algebraic Methodology and Software Technology. The book collects 24 revised full papers together with 3 system demonstrations and 3 invited talks. Coverage includes current issues in formal methods related to algebraic approaches and to software engineering including abstract data types, process algebras, algebraic specification, model checking, abstraction, refinement, mu-calculus, state machines, rewriting, Kleene algebra, programming logic, and formal software development.