The development of cost-effective wave energy technologies is a long and arduous process that entails numerous challenges. Many design decisions must be taken from the early development stages. A common evaluation framework based on objectivised criteria can contribute to keeping the right direction in the development process of wave energy technologies. Building upon the well-established Systems Engineering (SE) body of knowledge, this paper aims to address a significant part of the requirements that guides the specification of wave energy technology assessment criteria, metrics and tools. SE approaches such as the design domains framework, the multi-criteria aggregation logic, the fundamental relationships and utility functions can be used at different levels of system definition, technology maturity and markets to ensure a fully consistent, comparable and traceable assessment. Huge benefits can be obtained from the application of knowledge in earlier stages of wave technology development. After presenting and discussing the requirements for wave technology performance assessment, the paper draws some conclusions and propose future research work.