This study aims to explore the perceptions of foundation doctors (FDs) in the United Kingdom (UK) surrounding raising concerns in the workplace. An online survey was sent to all FDs in the UK between February and March 2018. Respondents were asked what they had observed or experienced that had been ethically challenging during their foundation training. The qualitative responses were coded into themes. Reasons why FDs wished to raise concerns in the workplace included disagreements about clinical decisions within the team, insufficient availability of resources, lack of senior colleague support and having to work beyond their competencies. Challenges faced by FDs when raising concerns included organisational resistance to change, difficulties in communicating ideas to those higher up in the hierarchy and the emotional stress of whistleblowing regarding senior colleagues. Perceived consequences of raising concerns included negative impact on FDs' reputation and career, and fear of bullying. To overcome these barriers, changes within organisations at all levels must take place in order to provide an environment where FDs are encouraged to raise concerns and thus make positive changes to their work environments for themselves, their colleagues and patients.