Along with enterprise architecture (EA) ontology and frameworks, metamodels are one of the most important tools available to the enterprise architect. The potential of a good metamodel compromises a dependence on a range of metamodels provided by vendors, EA modeling tools, or those that form part of an architecture framework. Typical metamodel sources include The Open Group Architecture Framework (TOGAF), ArchiMate, and The Essential Project, while tool vendors include Troux and Sparx Systems. Although there are many commonalities between these diverse sources, there is plenty of scope for improvements and consistency. The accompanying Executive Report examines current best practice to highlight effective metamodeling techniques and suggest ways that EA teams can improve their metamodels and metamodeling.