Education represents a key intervention point in encouraging the emergence of a professional engineering ethos informed by a sustainability ethic. In terms of establishing an appropriate relationship between sustainability and education, many would contend that incorporating sustainability as merely add-on material to already overcrowded curricula is insufficient. Instead sustainability should actually be a leading principle for curricula. Traditional reductionist models of engineering education seek to extinguish context and uncertainty and reduce complexity across socio-economic and ecological domains. They therefore constitute a wholly inadequate response to the need for fit-for-purpose, twenty-first century graduates required to address broader sustainability issues. This paper presents research from an undergraduate module at University College Cork, Ireland. The module is aimed at developing students' conceptions of complexity, uncertainty, risk, context and ethics as foundational bases for productively engaging with sustainability. The paper also highlights some problematic issues.