Despite increasing attention and calls for transdisciplinary (TD) working in engineering, a lack of clarity surrounding what constitutes a TD research approach persists. This paper aims to reduce ambiguity by characterising TD and identifying when the TD approach should or should not be used. Specifically, the research answers the question: when might it be beneficial to take a TD rather than a single, multi or interdisciplinary research approach? Survey responses from twenty-eight authors (50%) who presented papers at the 28 th ISTE International Conference on Transdisciplinary Engineering (TE2021) were qualitatively analysed. Findings show a TD approach to research is beneficial for complex problem-solving. New understanding reveals that TD could be used to evidence scientific and social impact, and that context determines the appropriateness of TD adoption. However, even where TD adoption is deemed appropriate, institutional barriers to adoption may exist. In other words, the work environment (culture) in which we do our research, may determine if any meaningful benefits from TD are, or are not realised. Lessons from engineering education are used to discuss how to institutionalise TD, future transdisciplinary engineers and researchers might be taught and socialised in the competencies needed for transdisciplinary research.