This paper aims to explore the potential role of Master's of Education dissertation/thesis work in developing twenty-first century skills. A total of 600 education professionals studying Master's of Education programmes in five countries -- Poland, Portugal, England, Latvia, and Romania -- were surveyed. The findings have revealed that participants recognise the usefulness of twenty-first century skills for their (future) professional practice, and perceive dissertation/thesis work as a valuable foundation for developing these skills. This study offers practical implications for designers of Master's of Education programmes and contributes to our understanding that this assignment is not only a formal requirement for obtaining a degree, but that it also serves as a pathway towards deepening students' professional learning.