Ethical capability is one of a suite of broad competencies that are recent inclusions in national and state curricula in Australia. Problems arise in how to support teachers to assess student progress in complex skill areas. Using methodology derived from the work of Griffin, this study investigated whether a criterion-referenced assessment framework, in the form of rubrics and a learning progression, could be developed for the construct of Ethical Decision-Making (EDM). Firstly, the domain of ethical competency was critically interrogated by examining curriculum documents, educational models, and empirical research into moral development. A construct of EDM and a derived skills framework were then presented to an expert panel of teachers. Over the course of two workshops, the panel critically reviewed the framework and co-constructed a set of rubrics. In a final iteration, the rubrics formed the basis for developing a hypothetical learning progression. Further research would be required to determine whether these assessment materials are useful to support teacher judgement about student progress and curriculum planning.