This commentary outlines a systems approach to patient safety at various organizational levels. The authors identify a number of factors that contribute to errors, including high workloads, inadequate supervision, and poor communication. They provide a human factors strategy for analyzing errors (The London Protocol), derived from James Reason’s model of organizational accidents, which differentiates active from latent failures. An emphasis is placed on fostering effective teamwork and building communities. An AHRQ WebM&M interview with primary author Dr. Charles Vincent describes his career as a patient safety pioneer.