Achieving an organizational safety culture is a widely espoused goal. The authors of this study synthesized qualitative and quantitative data from interviews, surveys, ethnographic case studies, board minutes, and publicly available datasets to describe the extent of safety culture in the United Kingdom's National Health Service (NHS). Culture was inconsistent across the NHS and barriers to safety culture included competing priorities, redundant regulatory and compliance requirements, lack of timely and actionable data, suboptimal organizational and information systems, and variations in staff and leadership commitment. The accompanying editorial highlights the finding that safety culture is mostly local, with high and low performing units existing within the same institution. The authors propose three actions to foster a safety culture: engagement of health care providers, establishment of peer networks, and explicit commitment between clinicians and leadership to prioritize safety.