Despite progress on patient safety since the Institute of Medicine 1999 report “To Err is Human”, significant problems remain. Human factors and systems engineering (HF/SE) has been increasingly recognized and advocated for its value in understanding, improving, and redesigning processes for safer care, especially for complex interacting sociotechnical systems. Broad awareness and adoption of HF/SE into safety improvement work, however, has been frustratingly slow. We provide an overview of HF/SE, its demonstrated value to a wide range of patient safety problems, in particular medication safety, and challenges to its broader implementation across health care. We propose seven recommendations and policy implications to maximize the spread of HF/SE, including formal and informal education programs, greater adoption of HF/SE by healthcare organizations, expanded funding to foster greater clinician-engineer partnerships, and coordinated national efforts to design and operationalize a system for spreading HF/SE into health care nationally.