This exploratory study investigates how nine London-based civil engineers have enacted ‘global responsibility’ and how their efforts involve ethics and professionalism. The study assesses moral philosophies related to ethics, as well as professional engineering bodies’ visions, accreditation standards, and requirements for continuing professional development. Regarding ethics, the study questions where the line falls between what an engineer ‘must do’ and what ‘would be good to do’. Although the term ethics did not spring to mind when participants were asked about making decisions related to global responsibility, participants’ concern for protecting the environment and making life better for people did, nonetheless, demonstrate clear ethical concern. Participants found means and mandates for protecting the health and safety of construction workers to be clearer than those for protecting society and the natural environment. Specific paths for reporting observed ethical infringements were not always clear. As such, angalyses suggest that today’s shared sense of professional duty and obligation may be too limited to achieve goals set by engineering professional bodies and the United Nations. Moreover, although professional and educational accreditation standards have traditionally embedded ethics within sustainability, interviews indicate sustainability is a construct embedded within ethics.